(written from a Production point of view)
Born in Chicago, Illinois, Marshall entered show business when she was hired as a showgirl at Chicago's Chez Paree at the age of 14, and began appearing in Las Vegas two years later. After moving to California, she began working in television in the late 1950s, with appearances on several Westerns (including an episode of Have Gun – Will Travel with Bill Erwin). She was subsequently cast to star in the adventure series Bold Venture, which last for 39 episodes during the 1959-1960 TV season.
She went on to appear in the 1961 cult horror movie Homicidal, which starred another one-time TOS guest star, Glenn Corbett ("Metamorphosis"), who later starred on The Road West (with Charles Seel), on which Marshall made a guest appearance in 1967 (with Willard Sage playing her husband). In 1962, she appeared in an episode of The Twilight Zone ("Dead Man's Shoes") with another TOS guest star, Warren Stevens ("By Any Other Name"); she and Stevens had previously co-starred together in two episodes of Hawaiian Eye. She later appeared in the 1964 musical Looking for Love, also featuring TOS guest stars Susan Oliver ("The Cage") and Stanley Adams ("The Trouble with Tribbles").
On television, she appeared with Madlyn Rhue in an episode of Bourbon Street Beat, with Kenneth Tobey in an episode of 77 Sunset Strip, with Tige Andrews in an episode of The Detectives, with William Schallert and William Wellman, Jr. on Gunsmoke, and with Stephen Brooks and Lawrence Montaigne on The F.B.I.. She and Montaigne also played relatives in two 1966 episodes of Dr. Kildare. Other TV shows on which Marshall appeared include Maverick, I Spy, and Bonanza. She also starred as Phoebe Munster in the first unaired pilot for The Munsters, but she was replaced by Yvonne De Carlo when filming on the show's first season began and the character became known as Lily Munster.
Her final acting appearance was a cameo in the 1975 film Shampoo, directed by her then-husband, Hal Ashby. Marshall passed away in Jamaica at the age of 61.