[3] In a survey conducted by the International Federation of Football History & Statistics (IFFHS) in 80 countries, he was placed among the best eight managers in the world, receiving his award at a ceremony held in Rothenburg, Germany, on 8 January 2001.

Gegiç attributed Terim's successes as a coach to the unique understanding of the game that he developed while playing as a central defender.

Although they did not perform well in the tournament, losing all their matches and not scoring any goals, qualification was still considered a great achievement for Turkish football.

His aggressive style of football and his tense relationship with club president and owner Vittorio Cecchi Gori made Terim popular among Fiorentina fans.

With new boys Brazilian Leandro Amaral and Portugal's Nuno Gomes doing well up front, with a steadier defence and with Portuguese playmaker Rui Costa blossoming under Terim's constant praise and encouragement Fiorentina became a strong team in Italy.

Even as Cecchi Gori was beginning to count the cost of sacking him, the fans made it clear that they were on the side of Terim.

The team's performance declined significantly from then on because of his continuing clashes with Cecchi Gori led Terim to resign on 26 February 2001, before the season ended.

Fiorentina director general Giancarlo Antognoni, one of the greatest players in the club's history, also resigned along with Terim's entire coaching staff, despite the fact that Cecchi Gori had begged him to stay.

[9][10] The Romanian football legend Gheorghe Hagi praised his work in Florence: "In five months he built up a phenomenal side at Fiorentina.

[12] On 18 June 2001, Terim signed a two-year contract with Milan replacing the caretaker manager Cesare Maldini.

[13][14][15] He transformed Milan's system, employing a style very similar to the total football of Rinus Michels, playing a 4–3–1–2 formation with Rui Costa as a key player, whom he brought from his previous team, Fiorentina.

Terim built a highly attacking side, but during this period Milan was also notorious for being vulnerable at the back, often conceding goals unexpectedly and drawing against "underdog" teams.

On 5 November 2001, after the 0–1 defeat against Torino his contract was terminated after only five months of work and he was replaced by Carlo Ancelotti,[16][17] despite the fact that Terim had received a vote of confidence from Milan vice-president Galliani following a 1–1 draw with bottom-placed Venezia in mid-October.

Terim brought back Ümit Davala and Hakan Ünsal from the UEFA Cup winning squad and transferred Felipe to the number 10 position.

[26] Turkey national team was sanctioned by a fine and six official home matches behind closed doors and on neutral ground by the FIFA.

Terim's contract was extended to 2012 at the conclusion of the tournament, despite heavy speculation that he might return to Italy or go to England to manage at club level.

In 2010 World Cup UEFA qualifying, Group 5, as of April 2009, Turkey had won two matches, drawn two and lost two, leaving them four points behind second-placed Bosnia and Herzegovina.

After internal conflict among board members, and the poor performance of the team during the 2010–11 Süper Lig season, Galatasaray appointed a new chairman, Ünal Aysal.

The top four teams in the regular season – Galatasaray, Fenerbahçe, Trabzonspor and Beşiktaş – entered the Championship Group of the European play-offs.

Galatasaray lost 3–0 at Santiago Bernabéu, but won the second clash 3–2 in Ali Sami Yen with a beautiful heel goal by Didier Drogba but eliminated from the European competition by losing on aggregate.

The club stated Terim had rejected an offer of a two-year extension on his current contract, which had been due to expire in June 2014.

As the news filtered out, dozens of supporters reportedly assembled in front of the training facilities to protest the decision, calling on the board to resign.

[32][33] On 22 August 2013, Terim was appointed interim manager of Turkey, replacing Abdullah Avcı, ahead of four critical 2014 World Cup UEFA Group D qualifying matches.

On 22 December 2017, Terim was announced as manager of Galatasaray, replacing Igor Tudor, on a contract that would have see him at the helm until the end of the 2018–19 season.

On 25 May 2019, during the cup ceremony at Ali Sami Yen, Galatasaray president Mustafa Cengiz announced that the club agreed on a 2+3 years new deal with Terim.

[40] On 19 July 2021, the recently elected Galatasaray president Burak Elmas announced that they have signed a 3-year contract extension with Terim.

However, early elimination from the Champions League (qualifying round) as well as many consecutive losses in Süper Lig (ended tenth by mid-season, 19 points behind the leader) caused lots of criticism of the coach by the fans and media.

However, after elimination against TFF First League side Denizlispor in the cup and a new defeat against Giresunspor at beginning of the second half of the season, many fans started calling the coach to resignation.

[46] On December 27, 2024, Saudi Arabian club Al Shabab appointed Terim as head coach, signing him on a six-month contract with an option for an additional year.