AEK Athens 2009–10 season Manolas began his youth career at
Thrasyvoulos in 2008. In 2009, his uncle
Stelios Manolas, who was the
technical director of
AEK Athens at the time, was scouting his nephew at a youth match with AEK manager
Dušan Bajević and was impressed with his performance. On 16 June 2009, Manolas signed a three-year deal with AEK. After signing, Manolas said, "I am very happy signing for the team I support, hopefully I can be a legend at the club like my uncle and end my career at AEK." He made his debut against
AO Kavala and was named
man of the match. After the game, he stated, "It's a dream to play for the club I love." Manolas was also rewarded with man of the match honours the following week against
PAOK. In his first seven matches, Manolas was named man of the match in five of them. Manolas scored his first professional goal against archrivals
Olympiacos on 19 May 2010. Although he was playing with a broken
jugal bone since the first minute of the match after a dangerous nudge by
Kostas Mitroglou, he scored in the sixth minute, though he later left the match in the 15th minute. He refused to be taken to the hospital before the match was over, despite being urged by his uncle
Stelios Manolas. The next day, he underwent a successful three-hour surgery, recovered and quickly returned to training sessions.
2010–11 season Manolas was a key figure for AEK Athens in the
2010–11 season, playing impressive performances in the
Super League Greece but also in the
2010–11 UEFA Europa League, which drew interest from many European teams such as
Genoa,
Udinese,
Getafe and
Schalke 04. Manolas scored a very important goal for AEK against
Hajduk Split, securing the win for the Greek side. The following week, Manolas found the back of the net again, this time against
AEL in the
Greek Cup, which AEK would later go on to win. His impressive performances convinced then AEK Athens coach
Manolo Jiménez and earned him a spot in the starting line-up, forcing
Real Madrid loanee
David Mateos to the substitutes' bench. Manolas developed massively while playing alongside AEK icon and
UEFA Euro 2004 winner
Traianos Dellas, stating to the press, "It is an honour to play alongside such a great player like Dellas, I have developed and become a better player. His experience has helped me become confident on the ball and the decisions I make in the game. I have learned a lot from him and he is basically like a teacher to me who I look up to." On 30 April 2011, Manolas won the first trophy of his career, the
Greek Cup. He played a large role in winning the trophy and played solid throughout the match against
Atromitos, where at one point he cleared an opposition shot off his line. Manolas also received man of the match honours due to his outstanding display. After the
0–3 victory, Manolas stated, "It is a dream for me to win a trophy with my childhood club AEK, and I hope there's many more to come in the future." He finished the 2010–11 season playing 36 matches, scoring three goals.
2011–12 season On 11 July 2011, Manolas signed a three-year contract extension with AEK, keeping him at the club until 2014. His contract was worth €900,000 earning €300,000 per-season including bonuses that could reach up to €1.4 million. Manolas renewed his contract despite interested from big European outfits
Werder Bremen,
Sevilla,
Wolfsburg and
Hamburger SV. Manolas agreed with AEK on €4 million buyout clause for foreign teams and a €10 million buyout clause for Greek teams. Shortly after signing the contract, Manolas stated to the press, "I am extremely happy that I am going to continue playing for the team of my heart and it is an honour to wear the AEK Jersey for the next three years with my childhood club. I applaud AEK president Stavros Adamidis who believes in me and declined great offers from European teams to keep me at the club despite the huge economical problems the club is suffering. My dream now is to become the team's captain and win the league just like my uncle Stelios Manolas, who achieved this when he joined AEK." Manolas started the season positively, playing his first competitive match of the
2011–12 season against
Georgian side
Dinamo Tbilisi in a
2011–12 UEFA Europa League qualifier, helping AEK to 1–0 victory. He was given heavy praise from Manolo Jiménez. Manolas scored his first goal of the season in a 0–1 away victory over
Panionios. He dedicated the goal to Jiménez, who had been taking criticism in recent weeks for his team's poor performances. Manolas also scored the first goal for AEK Athens in a 1–3 away win against Austrian club
Sturm Graz in the Europa League. During the January transfer period, the English
Premier League's
Everton showed sincere interest in the young centre back, with the team's then-manager
David Moyes stating, "Manolas has huge talent and is a player for the future." On 30 January 2012, it was said that AEK and Everton had agreed on terms to sell Manolas to Everton. Manolas, however, declined the offer, as he felt he would be leaving his club in a bad situation as the club would have only had three centre backs in the squad:
Traianos Dellas and two youth players
Mavroudis Bougaidis and
Elfar Freyr Helgason after the departure of loanee
Cala, who was recalled back to his club
Sevilla. AEK Chairman Stavros Adamidis stated, "It was Manolas who declined the offer, not AEK." He left AEK Athens having 85 appearances (6 goals) in all competitions.
Olympiacos 2012–13 season On 1 July 2012, Manolas joined rivals
Olympiacos on a free transfer until 30 June 2016 after his contract with AEK Athens had expired. "I am very happy that I'm at Olympiacos and I can't wait to play with the red and white shirt in front of a full Karaiskaki and our fans," Manolas said. At a time where AEK were struggling to pay off crippling debts, the departure of one of the club's key players came as another major blow. Ahead of the next season, AEK were only able to buy and sell Greek players up to the age of 22 and were barred from purchasing foreign players, as punishment for failing to meet the Greek
Super League's financial criteria. AEK were allowed to renew the contracts of any player already at the club, whether their highest earners would be willing to remain at a club that has a history of failing to pay player wages remained to be seen. Moreover, AEK were also banned from taking part in the Europa League that season by the
Hellenic Football Federation, with their place taken by
Asteras Tripolis. Manolas made his Olympiacos debut against
PAS Giannina on 15 September in a 1–2 away win, then scored his first goal for his new side against
Skoda Xanthi in a 4–0 home win.
2013–14 season Reports in Greece suggested that English clubs
Tottenham Hotspur,
Sunderland and
Fulham were all keeping an eye on Manolas ahead of the January transfer window. According to Gazzetta.gr, Manolas had captured the attention of Premier League scouts since moving to Olympiacos on a free transfer from AEK the previous summer. It was thought that Manolas could be interested in a move to the Premier League to push his case for continued inclusion in the
Greece national team manager
Fernando Santos' plans, with Greece at the time in second place in their
World Cup qualifying group behind
Bosnia and Herzegovina. Manolas, however, was unlikely to seriously consider any move that would see his chances of first-team football jeopardised. It was also reported that then-
Manchester United head coach
David Moyes targeted the Olympiacos defender as a replacement for
Nemanja Vidić after confirming the latter's departure from
Old Trafford at the end of 2013–14 season to
Internazionale, while United's other starting central defender,
Rio Ferdinand, would later follow his teammate out, leaving United short of quality in central defence. Moyes would end up being sacked and rumours of a move immediately ceased. Manolas scored his first goal for Olympiacos in the
2013–14 UEFA Champions League in a 1–0 home win against
Benfica, building the foundations for the next round. He scored his second goal in the Champions League in a 2–1 away loss against
Paris Saint-Germain, though nonetheless the squad secured a spot in the
round of 16—the first time the club had reached the stage since
2009–10—in matchup against Manchester United. With United failing to display their usual dominant domestic form that term, Manolas thought the Greek champions had what it takes to make the Champions League quarter-finals for only the second time: "I believe we will give a good performance. I hope Manchester United will not get better than they are now, so we can defeat them." Despite winning the first leg 2–0 at home, Olympiacos fell as Manchester United's
Robin van Persie hit a hat-trick in the return leg in
Manchester to progress 3–2 on aggregate. On 22 March 2014, Manolas extended his contract with Olympiacos for another year, keeping him at the club until the summer of 2017. He left Olympiacos having 73 appearances (6 goals, 2 assists) in all competitions.
Roma 2014–15 season On 27 August 2014, Italian
Serie A side
Roma announced the signing of Manolas for an estimated fee of €15 million. Upon joining Roma, Manolas said, "I had offers from several big clubs, including
Juve. But it was my decision to come here to Roma. I wanted to come to Roma. Lots of people told me good things. Their advice and my decision is what brought me here. The club has big goals. I want to win the
Scudetto, as does the whole squad. We can also go far in the Champions League." On 30 August 2014, Manolas made his official debut for Roma as they beat
Fiorentina 2–0 in the opening game of the
2014–15 Serie A season. On 17 September, he made his first European appearance with Roma in the
Champions League as they cruised to an impressive 5–1 victory over
CSKA Moscow. On 5 October, Manolas was sent off in a match against Juventus for retaliating after being fouled by
Álvaro Morata, who was sent off as well. The
Italian Football Federation (FIGC) subsequently banned Manolas for two games for his part in the altercation. Manolas' impressive first year with his club garnered interest from many other European sides, including Premier League giants
Arsenal, though the player's agent,
Mino Raiola, said that Manolas was not interested in discussing the rumours: "Kostas is a Roma player, and anyone who wants him will have to ask the club. All I can say is the lad has a contract until 2019. Roma paid a lot for him, and that means they have a lot of expectations for him." Manolas enjoyed an excellent first season in Serie A, cementing his place at the heart of manager
Rudi Garcia's defence as his side finished second in the league table. In the ensuing close season,
Arsenal offered Roma £15 million for the player, whom they originally tried to sign last summer before being beaten by Roma. On 19 June 2015, at the end of the
season, Manolas, via a Roma fan poll, was named the club's "best purchase of the season" after capturing 56% of the vote, in front of the likes of
Seydou Keita (18%) and
Juan Iturbe (8%).
2015–16 season Manolas began the
2015–16 campaign as the de facto leader of the Roma defence. According to
Tuttomercatoweb,
Chelsea manager
José Mourinho attempted to bring the Greek international to
Stamford Bridge the previous season, and will try again in the New Year, with Arsenal and Tottenham Hotspur continuing their interest. On 17 September 2015, after the 1–1 home draw against
2014–15 Champions League title holders
Barcelona, Manolas praised his club's tactical performance: "We played a great game on a tactical level. We've been doing well in defence, and I think it's an important step for the team," he told
Sky Sports. On 23 September, Roma's unbeaten start to the season ended after losing 2–1 away at
Sampdoria, with Manolas scoring an own goal. On 26 September, Manolas scored his first goal in the
2015–16 Serie A as Roma comfortably defeated newly promoted side
Carpi 5–1. He opened the scoring after netting
Lucas Digne's clever assist with his right boot besides the challenge in the box from Carpi's
Gabriel Silva. On 5 December, in a dramatic 1–1 away draw against
Torino in domestic league action, Manolas brought down
Andrea Belotti inside the area, whereupon
Maxi López coolly converted the subsequent 94th-minute penalty kick. Despite replays suggesting the Greek defender may well have gotten the ball in the challenge, the referee nonetheless awarded the penalty. On 11 December, towards the end of a
Champions League match against Belarusians
BATE Borisov, Manolas engaged in a quarrel with teammate
Miralem Pjanić for mishandling a ball possession. As reported by
La Gazzetta dello Sport, the two players continued the fighting into the team's locker room. On 17 February 2016, in a 1st leg
UEFA Champions League game for the last 16, he was the indisputable leader of the defence, despite the 2–0 home loss from the Spanish giants
Real Madrid. Manolas closed down
Karim Benzema quite well throughout the game. Most of the low crosses were taken care of well by him but he could do nothing about the two goals. On 20 April 2016, in a match for
Serie A, Manolas scored his second goal in the season, giving an assist in a glorious home win against
Torino F.C. 2016–17 season On 25 July 2016, coach
Luciano Spalletti has insisted that the international defender is happy at
A.S. Roma and will stay at the club, despite every summer speculations involving
Manchester United,
Arsenal and
Chelsea's interest about the Greek defender. Arsenal were so displeased by the way Roma handled the talks that they later refused to allow
Jack Wilshere to go there on loan. Manolas began the
2016–17 campaign as the de facto leader of the Roma defence. In September 2016,
A.S. Roma are obliged to pay the sum of €6.5 million to Olympiakos for the international defender. Roma did not want to sell the Greek defender this summer as Olympiakos had a 50% next percentage sale until this August. Roma also rejected a bid from
Arsenal in the region of €39 million for Manolas and therefore the player stayed put. Now Olympiakos will receive from Roma the fee of €6,5 million and Roma will activate the clause obtaining the 100% of the player. Manolas is considered the best marker of 'calcio' and
Barcelona have been following him for a while. The Greek international has always been on a list of defenders that Barcelona have been interested in. With
Thomas Vermaelen's loan to Roma they received an option to buy on Manolas at the summer of 2017. On 2 October 2016, he scored the second goal sealing a 2–1 home win against rivals
Inter, as well as made the Inter captain
Mauro Icardi disappear. On 18 October 2016, Manolas rejected
A.S. Roma's proposal on the extension of his contract, which expires in 2019, despite the fact that the management was ready to raise the salary of the Greek centre back from €1.8 million to €2.5 million per year. According to the newspapers sources, the 25-year-old international player saw that almost 12 players had a higher salary than his and now expects an improved offer. On 23 October 2016, Manolas reached 100 appearances with the jersey of Roma, in a 4–1 home win
Serie A game against
Palermo. On 31 October, he broke his nose in
AS Roma's 0–0 away draw against
Empoli, in a game where the Greek defender simply covered every possible hole, thus missing
Europa League clash against
FK Austria Wien and
Serie A match with
Bologna at the Olimpico, the Giallorossi said. On 4 December 2016, in one of the most spectacular Roman derbies in history, Manolas showed the usual ability both in anticipating and blocking his opponents, giving
Balde Diao Keita and
Ciro Immobile a very difficult afternoon. On 13 December 2016, Roma's center-back trio had an amazing performance, especially Manolas and
Federico Fazio who combined 15 clearances, 11 interceptions and won 12 duels. Manolas' impact surpassed just defensive duties as he assisted for
Radja Nainggolan's 1–0 winner against
A.C. Milan. On 18 December 2016, Manolas according to doctors' report, will be out for around two weeks after picking up another injury in Roma's 1–0 defeat to Juventus. Manolas was forced off in the latter stages at Juventus Stadium, and he will now miss Roma's match against
Chievo, the defender having already been struck down with a broken nose and muscle strain this season. On 8 January 2017, he returned to the squad playing as a late substitute in a 1–0 away win against
Genoa. On 25 May 2017, a week before the end of the
season, Manolas and
Diego Perotti came a step away from putting their hands on them during training. To avoid the worst, only the provisional intervention of teammates, along with
Luciano Spalletti's decision to send them to the dressing room without even finishing the training, helped to lower the tension.
2017–18 season Despite a possible move to
FC Zenit, following teammate
Leandro Paredes, during the summer of 2017 Manolas remained at Roma for the
2017–18 season. On 27 September 2017, he opened the scoring in a 2–1 away win against
Qarabağ FK in the
UEFA Champions League Group stage. On 2 December 2017, the Greek international renewed his contract with the Giallorossi, until 2022, with a release clause set at €35 million. On 15 October 2017, the Greek defender was substituted during the
Serie A match against Napoli that took place at the
Stadio Olimpico in Rome. The Greek defender was out for almost a month due to a Grade I strain of his left adductor longus (thigh) muscle. On 31 October 2017, he returned to the squad in a convincing 3–0
Champions League home game against English champions
Chelsea F.C. On 5 November 2017, he scored his first goal in
2017-18 season from an
Edin Džeko assist in a 4–2 away win against
Fiorentina. On 9 March 2018, he scored the first goal in a 3–0 win with a header against
Torino F.C. after an assist by
Alessandro Florenzi with a cross following a corner. After his goal, Manolas dropped to his knees and pointed to the sky in tribute to
Davide Astori, the Fiorentina captain who died on 4 March. On 4 April 2018, in a frustrating 4–1 away loss for
2017–18 Champions League quarter finals 1st leg to
FC Barcelona, Manolas scored Roma's second own-goal after a clearance that in turn hit the right post,
Samuel Umtiti and the Greek defender. However, Manolas more than compensated for the 1st leg performance as he brilliantly headed the final goal in the Giallorossi's 3–0 dominant victory over the Blaugrana in the return leg,
sending Roma to the Champions League semi-finals for the first time since 1984. On 21 April 2018, Manolas captained his first match with the club against
SPAL during a 3–0 away win in
Serie A, after receiving the armband from his teammate
Radja Nainggolan. Manolas was one of Roma's most consistent players over the course of the campaign, proving to be a reliable figure in the Italians' defence.
2018–19 season Despite the yearly summer rumours surrounding his possible departure from the club, Manolas remained at Roma for a fifth season, aiming to win his first title with the club during the 2018–19 season. On 27 August 2018, Manolas scored against
Atalanta, as he tapped in
Javier Pastore's chipped free kick at the far post, helping Roma complete a comeback from 3–1 down to 3–3 at the
Stadio Olimpico. On 7 November, Manolas scored with a glancing header from very close range, placing the ball high and in the centre of the goal, from an assist by
Lorenzo Pellegrini with a
cross following a corner, helping his club to a vital 2–1 away win against
CSKA Moscow in the
group stage of the UEFA Champions League. His impressive performance saw him included in
UEFA Champions League's team of the week the following day. On 15 November, Manolas was forced off during Greece's 1–0 win over Finland due to a blow to the adductor magnus muscle in his leg. On 6 March 2019, Manolas made his 200th appearance in all competitions with Roma in the second leg of the club's round of 16 UEFA Champions League tie against
FC Porto; Manolas played the full 120 minutes as Roma lost 3–1 at home to exit the Champions League. Reports from the Italian media later confirmed that the 27-year-old had strained a muscle, and would miss around three weeks of action, meaning that he would not be expected to participate in his nation's
UEFA Euro 2020 qualifying matches against
Liechtenstein and
Bosnia and Herzegovina.
Napoli 2019–20 season On 27 June 2019, Manolas was close to a move to
Napoli after Roma and the Neapolitan club reached a deal for the Greek defender. Manolas agreed to pen a five-year contract with the latter club, with annual earnings of €4.5 million (including bonuses). Napoli officially purchased the defender for €34m plus a €2m signing-on fee, effectively activating his release clause. However, in the agreement between the two Italian sides, Roma purchased defensive midfielder
Amadou Diawara for €18m plus €3m in add-ons. Manolas had also been linked with Juventus, Milan, and Arsenal. He officially signed for Napoli on 30 June. On 24 August 2019, he made his debut with the club, starting in the 4–3 away win against
Fiorentina. A week later he scored his first goal for the club in a thrilling 4–3 away loss against Juventus, netting a goal with a header after a beautiful free-kick from
Mário Rui. On 28 September, Manolas scored his second goal of the season with a header after
Nikola Maksimović's corner, helping his club seal a 2–1 home win game against
Brescia. On 31 December, Manolas was included in the
Roma Team of the Decade. On 29 February 2020, Manolas connected with
Lorenzo Insigne's free-kick from the right wing, thumping a header into the net to give Napoli the lead in a 2–1 home win game against
Torino. On 16 May, Manolas was the first Napoli player to get injured since training resumed after the
COVID-19 pandemic in Italy. His club did not mention how long he would be out for, but 'Corriere dello Sport' reported that he would miss six weeks.
2020–21 season On 20 September 2020, Manolas was a starter in a 2–0 away win against
Parma. On 12 January 2021, Napoli confirmed that Manolas had suffered a first-degree muscle injury. The Partenopei defender was replaced by Nikola Maksimovic after 15 minutes of the 2–1 win against
Udinese. On 8 February 2021, Napoli confirmed that Manolas would be out for three weeks, as he suffered a second-degree sprain and damaged the ligament in the right ankle. The Greek defender was substituted at the
Marassi and carried out tests at the Pineta Grande clinic. He made his return to the squad as a late substitute against
Sassuolo on 3 March, but conceded a late penalty which Sassuolo converted to end the match in a 3–3 draw.
2021–22 season In August 2021, it was reported that Olympiacos had started negotiations with Napoli for the purchase of Manolas, with the player telling the club that he desired a return to Greece. Despite the transfer rumours, he was a starter in the opening
Serie A match of the season against
Venezia. On 21 October 2021, Manolas suffered an injury during Napoli's
Europa League clash against
Legia Warsaw. He was forced off the pitch in the 72nd minute with a suspected muscle injury. In December 2021, having lost his place in the starting lineup to
Amir Rrahmani, Manolas again expressed his desire to leave the club. On 10 December, he made his first appearance for almost two months as a late substitute in a 3–2 home win game against
Leicester City in the Europa League.
Return to Olympiacos 2021–22 season On 16 December 2021, Napoli announced an agreement for the sale of Manolas to Olympiacos in January 2022. The fee of the deal was reportedly €2.5 million. On April 16, 2014, and in the second game of the semifinals of the
Greek Cup against
PAOK, Manolas had made his last appearance with the jersey of Olympiacos and eight years later, he came on as a substitute in the game against
Apollon Smyrnis in
Georgios Kamaras Stadium, replacing
Avraam Papadopoulos.
Sharjah In late September 2022, Manolas joined Emirati club
Sharjah. On 17 January 2024, after 18 months with the side, his contract was terminated by mutual agreement.
Salernitana On 8 February 2024, Manolas returned to
Serie A to sign a short-term deal with
Salernitana. He joined
Filippo Inzaghi's side on a contract that expired in June 2024.
Pannaxiakos On 16 October 2024, Manolas returned to his boyhood club,
Pannaxiakos in the
Cyclades FCA First Division, signing a one-year deal. He scored five goals on his debut against Marpissaikos five days later, as Pannaxiakos ran out 12–1 winners. ==International career==