[8] After graduating from San Fernando High School in 1959,[9] Farnon majored in theatre arts at Los Angeles Valley College, co-starring in at least one production—James Costigan's Cradle Song—with her sister and fellow San Fernando High alumnus, then still known as Charmian Farnon.

[11] In between, she featured prominently—as "MISS WEEKEND"—in the summer 1961 promotional campaign by the San Fernando Valley Times on behalf of its new "Friday" section.

In 1967, she appeared in an episode of I Dream of Jeannie as Major Nelson's date, selected by Jeannie with the use of a "computer machine" at a dating club, and in March, 1970, she was in an episode of Dragnet ("Night School"), where she played a fellow student attending a college course with Joe Friday (played by the show's, creator, producer and star, Jack Webb).

While playing a mother in a live-action commercial in 1973 for Flintstone vitamins, she was approached by voice director Wally Burr to audition for what was to be her most long-running famous role, Wonder Woman on Super Friends.

She has voiced various commercials, including Betty Crocker, Nivea, Kodak, National World War II Memorial, Oil of Olay, Scotchgard and Cartoon Network spoofs of The Super Friends.