After "I Spy" ended its run, Culp had perhaps his best film role, a lead in "Bob and Carol and Ted and Alice" (1969), a comic look at the swinging marriage scene. He made his feature directorial debut with "Hickey and Boggs" (1972), co-starring with Cosby as private eyes searching for a missing girl. The film did not win box office approval, and Culp returned to acting. In 1973, he made a guest appearance on "Columbo" (NBC) and, for the next several seasons, would appear as a different uppercrust murderer trying unsuccessfully to outsmart Peter Falk. Culp returned to series TV with "Greatest American Hero" (ABC, 1981-83) as an FBI agent who convinces a high school teacher to use a suit that will make him fly. He was also given a chance to write and direct episodes. After the demise of "Hero", Culp stated openly that he would act only occasionally and devote more time to pursuing a writing career. During this period he co-starred in several forgettable films (e.g. "The Castaway Cowboys" 1974, "The Great Scout and Cathouse Thursday" 1976). By the end of the 1970s, with former TV partner Bill Cosby enjoying renewed success, Culp admitted in a TV GUIDE interview that he had not succeeded in his quest to be a writer. He reteamed with Cosby for an episode of "The Cosby Show" and an "I Spy" reunion film for CBS. He played a wishy-washy US president in "The Pelican Brief" (1993), which starred Julia Roberts and Denzel Washington. Often aligning himself with progressive causes, Culp played a key cameo in "Panther" (1995) and remained in demand, often in "white man-oppressor roles" well into the decade.