Forrest attended Grand Canyon University, a member of the National Association of Intercollegiate Athletics (NAIA).

Forrest lead Grand Canyon to the 1975 NAIA Division I men's basketball tournament, where they defeated Midwestern State University 65–54 in the championship.

In the championship game, Forrest had 16 points, 12 rebounds, six assists, and four blocked shots, and was named the tournament's Most Valuable Player.

The Suns reached the Western Conference Finals in the 1979 NBA Playoffs before falling to the Sonics in seven games.

Forrest's nephew, Caleb (born 1986), played four years of college basketball at Washington State University.