Culp is widely known for his work in television. Culp first earned an international reputation for his role as Kelly Robinson on "I Spy" (1965–1968), the espionage series in which he and co-star Bill Cosby played a pair of secret agents. The 1980's brought him back to TV again, starring as FBI Agent Bill Maxwell on "The Greatest American Hero". He also had a recurring role as Warren Whelan on "Everybody Loves Raymond". In all, Culp gave hundreds of performances in a career spanning more than 50 years.