She appeared in episodes of 37 television series from the 1950s into the 1970s, including Bonanza, Wagon Train, The Time Tunnel, Maverick, 77 Sunset Strip, Laramie, Gunsmoke, The Adventures of Superman, Kraft Suspense Theatre, Daniel Boone, Perry Mason, and Batman.

[6] Fahey did her secondary education at Pemetic High School in Southwest Harbor, where she performed in musicals, plays, and took part in public speaking events.

[11] The following October, she enrolled at the Pasadena Playhouse[12] Unable to find acting work after her drama school stint, Fahey returned to Maine in late spring 1952.

Fahey served as one of the fashion model hostesses on Queen for a Day and did photo shoots and general publicity events for the station's advertisers and other programs.

[18] Fahey's first real break came in March 1955, when Warner Brothers gave her a small, uncredited part in what was then called A Handful of Clouds, but was later released as I Died a Thousand Times.

This show had three rotating series; Myrna Fahey had a feature role in the first episode of King's Row starring Jack Kelly and Robert Horton.

Publicity of a different sort came from syndicated columnist Harrison Carroll, who reported in December 1955 that she was at the Cocoanut Grove night club with Frank Sinatra associate Nick Sevano.

At the end of 1957, Myrna Fahey had her first professional stage role, with a principal part in the Pasadena Playhouse production of Holiday for Lovers, later made into a 1959 film.

[30] Fahey complained in a 1960 interview that she was being typecast in "good girl" roles because of what directors called her "moral overtones," even though she wanted to play darker and more complicated characters.

Fahey also appeared in a supporting role in "Duel at Sundown", a notable episode of Maverick with James Garner, featuring Clint Eastwood as a trigger-happy villain.

Fahey's image branched out in the 1960s, helped by House of Usher and a role on the Boris Karloff TV series Thriller that same year titled "Girl with a Secret".

After a rough love scene in the 1960 episode of Bonanza "Breed of Violence", in which Fahey cut her lip, the cast presented her with an award for "Best Slapper in a Filmed Series".