Ozil, 32, said it was a dream for him to play for Turkish Super Lig side Fenerbahce and thanked everyone at the club, adding that he has been supporting Fenerbahce since he was just a boy.
He said Nigerian Jay-Jay Okocha was his one of the favorite footballers from Fenerbahce's history and on the current squad praised the play of Greek midfielder Dimitris Pelkas.
Asked about returning to the German national team, Ozil-German born but with Turkish roots-said: "I wish success to the German national team but will never play for them again."
Ozil helped Germany win the 2014 FIFA World Cup in Brazil. In 2018, he quit the national team, citing "racism and disrespect."
Following the 2014 triumph, Germany's shocking group-stage elimination at the 2018 World Cup in Russia sparked more criticism of the team and Ozil.
He added that he will not go back to the Bundesliga, where he started his career with Schalke 04.
Ozil stressed that his target is not only doing well in the Super Lig, but also representing Fenerbahce in Europe in the best way possible.
Also at the ceremony, Fenerbahce Chairman Ali Koc said that he spoke with former Arsenal manager Arsene Wenger about Ozil's potential move to Turkey before meeting with Ozil in London.
"I got positive feedback [about Ozil] and I'd like to thank Wenger. It was a very productive conversation," Koc said.
Saying that the club's financial condition loomed large when he met Ozil in London in December, he added: "Mesut said wage was no issue and he just wants to be part of Fenerbahce."
Ozil will wear the number 67 jersey.
Fenerbahce will pay Ozil a total of €9 million ($10.9 million) during the three-and-a-half-year contract, along with a signing fee of €550,000.
Last week Ozil announced his move to the Turkish club.
During his career, Ozil made appearances for Germany's Schalke and Werder Bremen, Spain's Real Madrid, and England's Arsenal.
Ozil led Real Madrid to claim a Spanish La Liga title, a Spanish Cup, and a Spanish Super Cup.
He also played a critical role with Arsenal, which clinched four FA Cup trophies and reached the UEFA Europa League final in a span of just six years.
