Clark went on to amass numerous screen credits in roles of varying size, from Bob Younger in Philip Kaufman's "The Great Northfield, Minnesota Raid" (1972) to the deputy murdered by Kris Kristofferson in "Pat Garrett and Billy the Kid" (1973). Other roles have included the Secretary of Defense in the cult hit "The Adventures of Buckaroo Banzai: Across the Eighth Dimension" (1984), Uncle Henry in "Return to Oz" (1985) and the judge in "Class Action" (1991). He has also been a constant presence on TV and had regular or recurring roles on three series. Clark was the superior officer to Lou Antonio and Kim Basinger in the short-lived "Dog and Cat" (ABC, 1977). On the ABC sitcom "Grace Under Fire", he had the recurring role of Grace's father-in-law Emmett Kelly and was a co-worker of Jeff Foxworthy on his eponymous ABC sitcom in 1995-96. His longform credits include both "The Winds of War" (ABC, 1983) and "War and Remembrance" (ABC, 1988).
Clark stepped behind the camera to helm "My Dissident Mom", a 1987 "CBS Schoolbreak Special" and two episodes of the NBC series "Midnight Caller". He helmed his first (and to date only) feature in 1988, the adaptation of Hugh Leonard's play "Da" (1988). Clark cast his friend Martin Sheen in the leading role of an Irish-American who returns to Eire and confronts his relationship with his father (Barnard Hughes). Critics were divided over the effort and audiences were generally apathetic.