[3][4] When she was three years old, Harmon modeled clothes in Fox Movietone News newsreels.

[1] Harmon's stage debut came in Pajama Tops at the Klein Memorial Theatre in Bridgeport, Connecticut.

She toured the United States in stock company productions, including The Marriage-Go-Round, The Solid Gold Cadillac, The Tender Trap, The Importance of Being Ernest, and Susan Slept Here.

Harmon's stand-out acting roles include the 30-foot-tall (9 m) Merrie in Village of the Giants (1965, in which she captures normal-sized Johnny Crawford and suspends him from her bikini top), and the car-washing Lucille in Cool Hand Luke (1967)[7] with her purportedly 41–22–36 measurements.

[2] Harmon was married to film editor and producer Jeff Gourson from 1968 to 2001, raising three children.