She also appeared with Jerry Lewis in his 1957 film The Sad Sack and the 1956 film Back from Eternity. Kirk was a regular on The Red Buttons Show and appeared as a guest on some television programs, including an episode of The Twilight Zone (“A World of His Own”). As her acting career slowed down, Kirk began serving as an activist for various social causes. She vocally opposed death row inmate Caryl Chessman’s death sentence and visited Chessman in prison until his execution in 1960. After the Watts Riots in 1965, she funded preschool programs for underprivileged families in South Los Angeles.

Kirk’s marriage to television producer and screenwriter Warren Bush was announced in the press in early 1967, and lasted until his death in 1992. A Democrat, she attended the 1960 Democratic National Convention in Los Angeles, California.

She granted interviews and wrote for the American Civil Liberties Union newspaper. Kirk made her last onscreen appearance in a 1970 episode of The F.B.I. before leaving show business altogether to enter public relations. She worked as a publicist for CBS News, and retired in 1992.

On October 19, 2006, Kirk died of a cerebral aneurysm at age 79 in Woodland Hills, California. She was buried with her husband Warren Bush at Arlington National Cemetery in Virginia.