Reggie was a High School All-American at Inglewood where he averaged 29 points and 16 rebounds a game his senior year. The 6-7 Theus then went to UNLV to play for Jerry Tarkanian for three seasons, helping the Running Rebels advance to their first final four in school history in 1986. That team set NCAA records for most points and most 100-point games in a season. As a junior, Theus averaged 19 points, 6 rebounds and 5 assists per game in an All-American season. He had a 13-year NBA career starting as the first-round draft pick of Chicago, before turning to coaching. He made the All-Rookie team and the all-star team and was one of the assist leaders.

He coached in the NBA as head coach of Sacramento and was college head coach at both New Mexico State and Cal State Northridge. He was inducted into the UNLV Athletics Hall of Fame in 1989 and is only one of eight players with his jersey retired. His jersey was also retired at Inglewood HS. He also has worked in broadcasting and as a TV actor. He is the AD/basketball coach at Bethune-Cookman in Florida.