Few film-makers of the left emerged unscathed from the Hollywood witchhunt led by Senator Joe McCarthy. Some died, some were ruined, some headed for Europe. Others named names. Among its victims, the actor Betsy Blair, who has died aged 85, considered herself fortunate.

Despite being blacklisted, she was made less vulnerable by her marriage to fellow socialist Gene Kelly who, by the early 1950s, was virtually untouchable thanks to such succesful movies as On the Town, An American in Paris and Singin' in the Rain. Eventually she was nominated for a best supporting actress Oscar for her role in the 1955 film Marty.

Blair began acting in films in the late 1940s, with small roles in sturdy dramas such as The Guilt of Janet Ames, George Cukor's A Double Life and Another Part of the Forest, from the play by Lillian Hellman. She fell out of favour for activities that included substantial fundraising for leftwing causes. After Kind Lady (1951), where she nearly lost the part, she found herself unemployable. But, cushioned by wealth and a highly intelligent, inquisitive mind, she coped – still in her early 20s – with "committee" work, as wife to a superstar and mother to their five-year-old daughter.

Born Elizabeth Winifred Boger in Cliffside Park, New Jersey, she had started her career very early. After graduating from high school at 15 and being too impatient to wait to take up her scholarship at university, she went – with her teacher mother's connivance (her father was an insurance broker) – for an audition as a dancer in a New York night club. The teenager from a sedate, small-town background found herself in the big city, directed by and in love with the choreographer Gene Kelly.

She understudied the role of Laura in the Broadway production of The Glass Menagerie and took the lead in Willliam Saroyan's play The Beautiful People. When Hollywood beckoned, the newly married couple headed west, arriving in Los Angeles on the day the Japanese attacked Pearl Harbour, 7 December 1941.

Blair's initial disdain for movies allowed her to concentrate on theatre work, motherhood, keeping open house to the elite of Hollywood and fundraising. She was turned down by the Communist party, which feared that her joining might compromise Kelly's outside activities.

After a handful of parts and an enforced hiatus between 1951 and 1955, she was tentatively offered the role of Clara in the movie version of Paddy Chayevsky's teleplay, Marty. Thanks to pressure from the writer and Kelly, she was finally given the role, despite the blacklist.

The film, a tender portrait of a lonely butcher (Ernest Borgnine) and a plain girl who fall in love, became a sleeper: a critical and box-office success despite unknown actors and a small budget. It led to Oscar nominations for both leads. Borgnine took the best actor award. For Blair the outcome was different: "I got the nomination. I won the best actress award at the Cannes film festival and was hot for 200 days." She later took the best actress award at Bafta and found herself more famous in Europe than in America where, despite the accolades, she found no work, except in a Joseph H Lewis western, The Halliday Brand (1957). She left the US and Kelly for France, a Frenchman and a new life.

A small role in Tony Richardson's BBC TV production of Othello (1955) was followed by Meeting in Paris, a comedy with Claude Brasseur. More notice was paid to her next movie (in Spain) where she played a variation of her role as Clara. Calle Mayor (Main Street, 1956), directed by Juan Antonio Bardem, cast her as a small-town spinster who is duped into bed by the local lothario with a promise of marriage. Unfortunately for Isabel, he is doing it for a bet. During the shooting Bardem was arrested by the Franco regime but, thanks to international pressure, was released and completed the rather melancholy film to some acclaim.

Blair followed it with Il Grido (The Cry, 1957), directed by the great Michelangel