[1][2] When Bob Kloppenburg became head coach of California Western (later U.S. International) University, Gary Kloppenburg later attended La Jolla High School in La Jolla, California, graduating in 1971.
[3] From 1972 to 1974, Gary Kloppenburg attended Feather River College and played on the basketball team.
[3] Kloppenburg then played semi-professional basketball in Europe, first with the English National League in 1975–76 then in the Netherlands in 1977.
In the 2019 season, Kloppenburg served as interim head coach during the time Hughes was recovering from cancer surgery.
On June 29, 2020, Kloppenburg became head coach again after Hughes was determined to be at higher risk of illness from COVID-19.