After playing for several football clubs including Vefa, Fatih Karagümrük, Rizespor, Kahramanmaraşspor, Bakırköyspor, and Kasımpaşa, he joined İstanbulspor where he spent the longest time and also served as the team captain.

During his tenure, he trained notable players such as Arda Turan, Aydın Yılmaz, Uğur Uçar Ferhat Öztorun, Mülayim Erdem, Mehmet Güven, and Cafercan Aksu.

In the knockout stage, they defeated Croatia in the semi-finals and Netherlands in the final to become the European Champion for the second time in their history.

In addition to his successful stint at İstanbul Başakşehir (formerly known as Istanbul BB) Abdullah Avcı received a contract from the Turkey national team.

On 17 November 2011, after Guus Hiddink left his job, he was appointed as the coach of the Turkey national football team, which was vacated.

Having failed with only 6 wins and 4 draws in 18 matches with the national team, Avcı resigned from his position on August 20, 2013, after the rumors of the search for a new coach were not denied.

After his stint as coach of the Turkey national football team, Abdullah Avcı returned to İstanbul Başakşehir in the 2014–15.

Despite winning 11 matches at the start of the season, Beşiktaş's performance declined significantly, which led to Avcı's sacking on 25 January 2020, after only seven months as the coach.

It is worth noting that the team's disappointing results and the lack of support from the fans played a significant role in Avcı's departure from the club.

Avcı led Trabzonspor to win the 2020 Turkish Super Cup on 27 January 2021, and later on 30 April 022, they won the Süper Lig championship three weeks before the end of the 2021–22 season by drawing 2–2 with Antalyaspor.

On 7 March 2023, Avcı resigned from his position as Trabzonspor coach for personal reasons, leaving behind a successful legacy.

The team finished 3rd in the Süper Lig, securing qualification for the UEFA Europa League second qualifying round with a record of 21 wins, 4 draws, and 13 losses, accumulating a total of 67 points.

Despite a valiant effort, the team suffered a heartbreaking 3–2 defeat to Beşiktaş, conceding a last-minute goal at the Atatürk Olympic Stadium in Istanbul.

The team struggled in European competitions, being eliminated first from the UEFA Europa League in the third qualifying round after a 3–0 aggregate defeat to Rapid Wien (0–1 at home and 0–2 away).

On 31 August 2024, following these setbacks and continued poor performances domestically, Trabzonspor officially parted ways with Avcı during the early stages of the season.