Djurgårdens IF Amartey started out playing for second-tier club
International Allies in Ghana where he was spotted as a sixteen-year-old by
Magnus Pehrsson who was on a scouting trip in
Africa during his preparation to take over as manager of
Djurgårdens IF. When Pehrsson became manager he secured the transfer rights for Amartey from the day he turned 18. To help prepare Amartey for his future permanent move to
Sweden in 2013, the club brought him over for shorter periods of time in both 2011 and 2012 where he got to play for the club's U21 team. Amartey made his
Svenska Cupen debut on 3 March 2013 against
Umeå FC. He then made his league debut in the
2013 Allsvenskan opening game away against
Helsingborgs IF on 31 March. Amartey was praised by the media for his strong start to the 2013 season, and foreign clubs like
FC Schalke 04 and
1. FC Kaiserslautern started to scout him. On 26 May 2013, he scored his first ever goal for the club when he headed home the 1–1 equalizer in the
2013 Svenska Cupen Final which Djurgården eventually lost against
IFK Göteborg on penalties. After his first season in the Swedish league as an eighteen-year-old Amartey was ranked as the 10th-best player in the league by newspaper
Expressen and 18th best by
Aftonbladet. In November 2013 Amartey confirmed that he was in talks with
Liverpool F.C. over a possible move to the English club.
Copenhagen In July 2014, Amartey moved to
F.C. Copenhagen for a fee of €2.5 million plus add-ons, and made his
Superliga-debut on 20 July 2014, in a match against
Silkeborg IF.
Leicester City in 2021 On 22 January 2016, Amartey joined
Premier League side
Leicester City on a four-and-a-half-year contract for a fee around the region of up to £6 million. In his first season in his new country, Amartey featured five times as his team Leicester City won the Premier League title. He made his debut for the club on 27 February 2016, in 1–0 home league win over
Norwich City. In the 2016–17 season, Amartey became a first team regular following the departure of
N'Golo Kanté. partnering teammate
Danny Drinkwater in the central midfield role. While his workrate roughly equalled Kanté's, he has been unable to match his tackles and interceptions. On 14 September 2016, Amartey started in his
Champions League debut for Leicester in a 3–0 away win over
Club Brugge in the
group stage. Amartey scored his first goal for Leicester in an 88th-minute equaliser away at
Stoke City on 17 December 2016, salvaging a 2–2 draw. On 8 February 2017, just over 12 hours after returning to Leicester from international duty, Amartey played 120 minutes (including
AET) in a 3–1
FA Cup fourth-round replay win over
Derby County. In October 2018, Amartey broke his ankle in a game against
West Ham United, ruling him out for the rest of the
2018–19 season. Out of action for nearly a year, the closest Amartey came to a first team return was making the bench for an
EFL Cup match against
Luton Town in September 2019. He made his first team return almost two years after his injury in an
EFL Cup match against
Arsenal on 23 September 2020, which Leicester lost 2–0. Four days later he made his Premier League return when he started away at
Manchester City in a 5–2 win. On 18 February 2021, Amartey started in his
Europa League debut for Leicester in a 0–0 away draw against
Slavia Prague in the first leg of the
Europa League round of 32 tie. On 6 March 2021, Amartey scored his first goal for the Foxes in over four years, heading in a late winner to seal a 2–1 away league win over
Brighton & Hove Albion. On 15 May 2021, following Leicester City's
FA Cup final victory over
Chelsea, Amartey was filmed picking up a Chelsea
pennant in the Leicester dressing room and throwing it over his shoulder to the floor in a video that went viral. He received criticism and backlash from many social media users, who deemed the gesture disrespectful. Leicester City later issued an apology to Chelsea, who accepted. Amartey and Leicester started the
2021–22 season with the
2021 FA Community Shield against
Manchester City. Amartey played the full match as Iheanacho scored the winning goal, an 89th-minute penalty against his former club. On 5 June 2023, following the club's relegation from the
Premier League, it was announced that Amartey and six other first team players would be leaving the club upon the expiration of their contracts at the end of the month.
Beşiktaş On 21 July 2023, Amartey signed a contract with
Süper Lig club
Beşiktaş. On 13 September 2024, Amartey's contract has been terminated with Beşiktaş for an undisclosed reason. ==International career==