 After one season as an assistant, he succeeded Andy Pilney as head football coach at Tulane.O'Boyle managed only a 6–33–1 record in four seasons before he quit his post at the end of the 1965 season, a campaign that ended with a 62–0 loss to the rival LSU Tigers.The following year O'Boyle moved to the ranks of professional football, joining the Kansas City Chiefs of the American Football League (AFL) under head coach Hank Stram, with whom O'Boyle had worked as a fellow assistant at Miami.