In 2009, Hussein was spotted as a gifted teenager with his local team and it was because of a local resident who was also a board member at the
Al-Alam SC who recommended the player to his club. He played for youth Al-Alam in the provincial league, and for the first team and then moved to
Tuz FC, and with no club from
Kirkuk in the top divisions in the Iraqi league, Aymen took the unorthodox route in his attempts into getting into a top flight of the
Iraqi Premier League by signing for
Gas Al-Shamal a club which was then in the second tier of the Kurdistan League, a division formed of primarily reserve players from the top Kurdish clubs.
Duhok At the end of the season 2012–13, Hussein was offered the opportunity to play in the
Iraqi Premier League for the first time when he was contacted by the assistant coach of
Duhok,
Khalid Mohammed Sabbar and was offered a lucrative contract to play for the club which Hussein said he agreed to immediately amid “great joy” working under the former Iraq captain and the two renowned coaches Syrian
Fajr Ibrahim and
Thair Ahmed during his spell with Duhok. He appeared only a few times for Duhok scoring one goals in the first stage of the season, however with salaries going unpaid for months at the cash-strapped club feeling the full ramifications of the financial crisis which had hit the Kurdistan region, Hussein made the decision to try his luck in Baghdad. He had been one of six players at Duhok released due to their financial troubles during the latter part of the 2014. His breakthrough season came in the 2016–17 season for Al Naft, where he scored 12 goals in 10 games launching Al Naft to the top of the league, before an injury prevented him sidelined all the way from February till May. Al Naft continued on their impressive set of results and ended up finishing as the league runners up, which is their best ever result.
Al Shorta On 22 August 2017, Hussein signed for Iraqi giants
Al Shorta, to replace
Marwan Hussein. He made his debut on 21 November, scoring in the matchday one fixture against
Karbalaa FC. He scored twice in his second game, a 4–1 win over
Al-Bahri, he then scored in two more games, to extend his scoring record to four games in a row. On the fifth game, Hussein missed a last-minute penalty to end his goal-scoring streak. Aymen would then leave the Al-Shorta to join the Iraqi U-23 side in the
2018 AFC U-23 Championship in China, despite the club's objections. After his return from the national team, Al Shorta released him from his contract as he was set to join Qatari side
Al Ahli, however negotiations fell through in the final stages. He then returned to his former club Al Naft, despite Al Shorta insisting his release was conditional on him joining Al Ahli.
Return to Al Naft On 2 February 2018, Hussein returned to his former club Al-Naft with his favorite coach Hassan Ahmed. Hussein started his first match with Al Naft against
Al-Hudood FC, he missed a penalty and another against
Naft Al-Wasat. After five games he scored goal against
Al-Talaba in the 1–0 victory in April and continued to score. He finished his season with Al Naft with 11 goals in 22 matches in the league. The team finished in 3rd position. He was released from Al-Naft after the game against
CS Sfaxien 1–1, because of disagreements.
CS Sfaxien On 15 September 2018, Tunisian club
Sfaxien announced on the last day of the summer
transfer window the signing of Hussein on a three-year contract. Hussein was set to be paid 450,000 dollars per season. He did not make any appearances in the first half of the season due to a paperwork error, rendering him ineligible to play competitive games for the side. He made his first appearances in the Tunisian league in February 2019. Aymen struggled to get consistent gametime, mainly due to his lack of match fitness after missing the first half of the season. In July 2019, Aymen requested his release from Sfaxien due to the lack of playing time, and expressed his wishes to return to Iraq Aymen's contract was terminated by mutual consent, but he did not receive a compensation payment. He then sued the club, and FIFA ruled in his favor, ordering the Tunisian side to pay him 50,000 US dollars.
Al Quwa Al Jawiya On 5 August 2018, Aymen officially returned to the Iraqi league, joining Al Quwa Al Jawiya on a one-year contract. On 22 February 2020, he scored his first hat-trick with the club in a 3–0 victory against
Al-Sinaat Al-Kahrabaiya SC. The season was suspended due to the
October protests in Baghdad and then cancelled all together due to the
COVID-19 pandemic. The following season, Aymen had his best year yet, scoring 22 goals to end the season as the top goal scorer, leading his club to the title. It was the first league title of Aymen's career, as well as his first golden boot award. Following this successful season, Aymen received attention from clubs abroad, including Egyptian giants Al Ahly, and clubs in Algeria, Iran, and the United Arab Emirates, and the striker stated his intention to try playing overseas once again.
Umm Salal In summer 2021, Hussein joined
Umm Salal in Qatar. Aymen scored 11 goals in 22 matches, averaging a goal every other game in the Qatrai league. He finished as the league's 5th highest top goal scorer, and helped Umm Salal secure a 6th place finish. In July of 2022, Umm Salal announced that the player will not be renewed, and thanked the player for his services.
Al Markhiya and Al Jazira In July 2022, newly-promoted side Al Markhiya signed Aymen Hussein, to keep the player in Qatar. Aymen led his side to a shocking win over Qatari giants Al Sadd, after scoring 2 goals and assisting another in a 4–3 victory, which marked his side's first ever league win over Al-Sadd. The following week he scored once again to rescue a point for his team against
Qatar SC. Aymen was given permission to join the Iraqi national team during the
Arabian Gulf Cup, despite the league season still ongoing. Due to his great performance in the first half of the season, which was followed up by being the joint top goal scorer in the Arabian Gulf Cup tournament, Aymen attracted the attention of Emirati giants Al Jazira. On 7 February 2023, Aymen Hussein joined Al Jazira on a two-and-a-half-year deal. He was meant to be a replacement for the club's captain and talisman
Ali Mabkhout, who was set to leave the club in order to complete his mandatory service with the
United Arab Emirates Armed Forces. However, the player's service was delayed, meaning he was able to finish the season with his club. This led to Aymen struggling for playtime as he only featured 6 times, mainly off the bench. He scored his only goal vs
Al Bataeh Club. The team finished in fifth position, 9 points away from winner
Shabab Al Ahli. On 24 May, Aymen's contract was terminated by mutual consent.
Raja CA and return to Al-Quwa Al-Jawiya On 23 August 2023, Hussein signed a renewable one-year contract with Moroccan side
Raja CA. Aymen found it difficult to adapt in Morocco, and struggled with his form. He also struggled personally as the strained diplomatic relations between Iraq and Morocco made it difficult to get the paperwork necessary to relocate his family to Morocco, he thus asked for his release but was persuaded to stay by management. After failing to score in his first 5 games and repeated attempts to relocate his family had failed, he once again requested that his contract be terminated, and was granted his release by the Moroccan club. The club went on to win the Moroccan title that season. In October 2023, Aymen returned to Al Quwa Al Jawiya in Iraq. Aymen has his best goal scoring season of his career, scoring 27 goals in the league campaign, winning the Iraqi golden boot for a second time. However, his season had a bitter end, as his team fell short to local rivals Al-Shorta in both the league and the cup, finishing runners up to them on both occasions.
Al Khor and loan to Al-Wakrah On 16 July 2024, Qatari side
Al Khor announced that they have signed Ayemn Hussein on a two-year deal This marked the third club in Qatar that Ayemn Hussein has signed for. He joined the club late for pre-season due to his participation with Iraq in the Olympic games, regardless he started his first game two days later, in a goalless draw against Al-Gharafa. In September that year, he suffered a rib injury during the first international break of the season, which kept him out of action for a month, missing 3 league games for Al-Khor. In February 2025, he joined
Al-Wakrah on loan until the end of the season.
Al-Karma In August 2025, Hussein returned to Iraq, joining
Al-Karma for a record transfer fee of 1.25 billion Iraqi dinars. ==International career==