Phyllis Kirk was born in Syracuse, New York, though some sources state her birthplace as Plainfield, New Jersey. She contracted polio as a child, which resulted in health problems for the rest of her life. As a teenager, Kirk moved to New York City to study acting and changed her last name from Kirkegaard to Kirk. She began her career on Broadway before embarking on a television and film career. Phyllis Kirk is best known for her many roles throughout the 1950s. She appeared with Vincent Price in the 3-D horror film House of Wax (1953). Her most notable television role was opposite Peter Lawford in The Thin Man (1957–1959), where they played Nick and Nora Charles. A newspaper columnist described what distinguished Kirk’s role in the program: “[I]t’s her brains that keep her flying high on ‘The Thin Man’ series.” 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.

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