McCrea was born in DuBois, Pennsylvania to a Greek mother and Scottish father. She attended a modeling school, and became a cover girl and model. She met Bing Crosby, who encouraged her to move to Hollywood, California.

McCrea began her acting career in 1952, appearing in the film Deadline – U.S.A. playing the uncredited role of "Sally Gardner". She also guest-starred in television programs including Bachelor Father, Mr. Adams and Eve, and The Twilight Zone.

In 1963, McCrea was cast as Midge Kelsey in The Donna Reed Show. She remained with the series until its end in 1966. Her character was the best friend of Donna Stone (Donna Reed) and a neighbor on the show's fictional cul-de-sac.

After The Donna Reed Show, McCrea continued to work in television, appearing in shows such as The Love Boat, Fantasy Island, and Murder, She Wrote. She also appeared in a few films, including Will Success Spoil Rock Hunter? (1957) and Girls, Girls, Girls (1962).

McCrea retired from acting in the early 1980s. She currently resides in California.