 McCullum was hired as the head men's basketball coach at South Florida on April 18, 2003 by athletic director Lee Roy Selmon.In four seasons, McCullum was 40-76, and was fired after the 2006-07 season on March 9, 2007.After South Florida, McCullum coached the Nigerian men's national basketball team where he led the team to a 4-1 record at the All-Africa Games.