Investment banker Dalman takes over from Simon Lim, who had been acting chairman following Dato Chan Tien Ghee's decision to stepdown in March.
Lim will continue as the Bluebirds' chief executive.
Cypriot Dalman, who has previously worked with Deutsche Bank and Credit Suisse, told the club's official website: "I am honoured to take up the role of club chairman at Cardiff City Football Club.
"I have enjoyed my time at the club since joining the board of directors in January 2012 and now relish the opportunity to contribute further in my additional role as chairman with Cardiff City in the Barclays Premier League."
Club owner Vincent Tan, who last week reached agreement with finance company Langston over the club's long-standing debt, added: "I am delighted to welcome Mehmet Dalman into his new and additional role at Cardiff City Football Club and look forward to many successful years ahead.
"Mehmet has had many years of experience in business across the world which he has brought to this great club since becoming a non-executive director in January last year.
"This is more great news for the football club following last week's amicable resolution with the Langston Corporation in which Mehmet played a big role. I wish him the best of luck in his additional role at Cardiff City."
- Sports & Recreation
- Cardiff City Football Club
- Mehmet Dalman
- Barclays Premier League
- Chan Tien Ghee