Colangelo, however, will continue in the chairman's role through the 2005 season. Beginning on Jan. 1, 2006, he will carry the title of chairman emeritus.
Former sports agent Jeff Moorad will assume the CEO role on Oct. 15.
"We will forever be indebted to Jerry Colangelo for the role he has played in creating and building this great franchise, as well as his role in our community, the state of Arizona and Major League Baseball," Moorad said.
Colangelo has been the owner of four sports teams in the Phoenix area. He also has held a controlling interest in the NBA's Phoenix Suns, the Arizona Rattlers of the Arena Football League and the Phoenix Mercury of the WNBA.