The midfielder's contract in north London was set to expire in June, but the two parties agreed to write off the last few months on his deal. He started the opening 10 Premier League matches of Mikel Arteta's managerial reign until his last Arsenal appearance on March 7, 2020.
"The support I have felt from the team and fans during my time here has been truly incredible and something I will always be grateful for," Ozil said in a statement. "Together we won trophies for the first time in years and created memories that will last a lifetime. The Arsenal fans will forever remain in my heart.
"I'd like to thank (technical director) Edu Gaspar for helping bring about a professional and dignified solution in the past few days, and I wish everyone at the club the best in their attempt to continue to bring Arsenal back to the top, where we belong."
There are multiple theories as to what caused the breakdown of Ozil and Arsenal's relationship.
The World Cup winner refused to take a pay cut amid the current financial crisis after board members couldn't assure him that the savings would be used to protect club staff; the Gunners were keen to distance themselves from his tweet in December 2019 that denounced the Chinese government's treatment of Uighur Muslims in Xinjiang; and at regular intervals throughout his time at Arsenal, Ozil was accused of producing subpar performances and complacency by some football fans and sections of the media.
Arteta left his former teammate out of Arsenal's Premier League and Europa League squads this season. In his spare time away from the squad, Ozil has taken to social media while supporting Arsenal from home, has made numerous donations to charities serving the north London area, and infamously offered to pay the salary of Jerry Quy, the man who spent 27 years dressed as mascot Gunnersaurus, after the club laid him off.
Ozil won three FA Cups during his time with Arsenal and notably notched 19 assists when the side missed out on the Premier League title to Leicester City in the 2015-16 campaign. His last international cap came during Germany's group-stage exit from the 2018 World Cup.
"Mesut's achievements at Arsenal are undisputed," Arteta said. "It was a privilege to play alongside him and, more recently, coach him. His creativity and vision led to many goals during his time in the Arsenal shirt. Mesut was at the heart of many great moments for this club over the years, including those three FA Cup final wins. These successes will always be part of our history."
His new teammates at Fenerbahce include former Newcastle United striker Papiss Cisse and Enner Valencia, the Ecuadorian forward who played for West Ham United and Everton. The club finished seventh in the 2019-20 Super Lig term.