She began her career in film and television after appearing opposite Jon Voight and Faye Dunaway in A Streetcar Named Desire, eventually co-starring with Ronny Cox as the female lead in her own television series, CBS-TV's Apple's Way in 1974. She appeared in a variety of television series and miniseries throughout the 1970s, including Washington: Behind Closed Doors and the Quincy ME episode Eye Of The Needle playing a Holistic practitioner. In 1979, she appeared in Real Life.

McCain continued to work in television after relocating to the San Francisco Bay Area in the late 1980s and also appeared in Scream (1996) as the mother of Rose McGowan's character, and Patch Adams (1998).

She earned a Master's Degree in Psychology from the California Institute of Integral Studies in 2000, and continues to work in Theater extensively in the San Francisco Area.

In 2004, McCain initiated a theater project based on oral histories of the blue collar workers responsible for the building and maintaining of the Los Alamos National Laboratory in New Mexico which received workshop readings at the Lensic Center for Performing Arts in Santa Fe, New Mexico, most recently at the National Museum of the American Indian in Washington, D.C. She is an Associate Artist of the ZSpace Studio in San Francisco, and is an ensemble member of the AlterTheater Ensemble in San Rafael, California.