Clarke married Alyce King in 1956. They remained wed until her death in 1996. He was the father of actor and voice artist Cam Clarke.

From the 1950s through the 1980s, he regularly appeared on television series, including appearing on The King Family Show (1965),. He made two guest appearances on Perry Mason, including the role of circus co-owner and murderer Jerry Franklin in the 1960 episode, “The Case of the Clumsy Clown” and as Jack Harper in the 1957 episode “The Case of the Crooked Candle”. Other television appearances included The Lone Ranger, The Cisco Kid, Men Into Space,The Man and the Challenge, Hawaiian Eye, 77 Sunset Strip, Wendy and Me, General Hospital, Marcus Welby, M.D., Dragnet, Adam-12, Sea Hunt, Ripcord, Sky King, Checkmate, M Squad, Daktari, Baa Baa Black Sheep, Hawaii Five-O, Tabitha, Trapper John, M.D., Fantasy Island, Dallas, Simon & Simon, Knight Rider, Murder She Wrote, Matt Houston, Hotel, Dynasty, Falcon Crest, and dozens of others. The 1997 biographical documentary Lugosi: Hollywood’s Dracula featured narration which he provided. Clarke’s last appearance was in the movie The Naked Monster, a send-up of the classic science fiction films of the 1950s, in 2005.

Clarke revealed in his 1996 autobiography To ‘B’ or Not to ‘B’ (co-written by Tom Weaver) that he made The Hideous Sun Demon for less than $50,000, including $500 for the rubberized lizard suit he wore. He shot the movie over 12 weekends to get two days’ use of rental camera equipment for one day’s fee. The Hideous Sun Demon was featured in the 1982 movie It Came from Hollywood, and with Clarke’s permission, was re-dubbed into the 1983 comedy What’s Up, Hideous Sun Demon (aka Revenge of the Sun Demon) featuring the voices of Jay Leno and Cam Clarke reprising his father’s role.

In the mid-1960s, he served as spokesperson for a furniture and appliance store chain called Gold’s Giant Stores. His autobiography, To “B” or Not to “B”: A Film Actor’s Odyssey, was published in 1996. In the late it’s Clarke co-wrote “The Hideous She Demon” with Michael Goodell, published in Graphic Novella format for EMGEE Comics, and completed as a Screenplay/Shooting Script for EMGEE Studios and Krashenburn Films.