Marsh became one of the attractive young actresses who were regularly romanced by the stars of popular TV series, including The Man From U.N.C.L.E. (S3E21, "The It's All Greek to Me Affair", 1967 Feb 03), I Spy, The Wild Wild West (S1E14, "The Night of the Howling Light", 1965 Dec 17), It Takes a Thief (S1E11, "To Steal a Battleship", 1968 March 26), Hawaii Five-O (S02E07, "Sweet Terror", 1969 Nov 05; S03E07, "Forces of Waves," 1970 Oct 28; S12E06, "Image of Fear", 1979 Nov 08), and Daniel Boone (S6E19, "A Matter of Vengeance", 1970). Among her early television appearances she played Elizabeth Bacio, daughter of the title character, in the 1965 Perry Mason episode, "The Case of the Sad Sicilian." Appeared as Nora in The Big Valley (S4E16, "The 25 Graves of Midas", 1969 Feb 3).