Massoum, 76, is one of the founders of current President Jalal Talabani's Patriotic Union of Kurdistan party. He is considered a soft-spoken moderate, known for keeping good relations with Sunni and Shiite Arab politicians.
The vote for president -- a largely ceremonial post -- was delayed for a day when the Kurdish bloc requested more time to select a candidate. They named Massoum as their pick late Wednesday.
Under an unofficial agreement dating back to the 2003 U.S.-led invasion, Iraq's presidency is held by a Kurd while the prime minister is Shiite and the parliamentary speaker is Sunni.