Born Beatrice Joan Caulfield while her family resided in East Orange, New Jersey, she moved to West Orange during childhood but continued attending Miss Beard’s School in Orange, New Jersey. During her teenage years, the family moved to New York City where Joan eventually attended Columbia University. Caulfield was the niece of Genevieve Caulfield, who received the Presidential Medal of Freedom in 1963 for her work with blind children. While at Columbia, Caulfield was active in many plays presented by the university’s drama group. She also ventured into being a model with the Harry Conover Agency and “became a favorite with top-drawer fashion magazines,” with her pictures appearing in many national magazines, including being on the cover of Life magazine’s May 11, 1942, issue. Caulfield appeared on Broadway in Beat the Band in 1942. She had a great success portraying the troublesome teenager Corliss Archer in the 1943 hit comedy play Kiss and Tell. After a year in the role she left the production to pursue offers from Hollywood and she was replaced by her sister Betty Caulfield. Being the subject of an episode of This Is Your Life brought Caulfield to the attention of television executives. In the words of a newspaper writer, “She photographed so beautifully that the show was hardly over before she was being approached for television appearances.” She appeared on programs such as Cheyenne, Baretta, and Murder, She Wrote, with Angela Lansbury. In the 1957–1958 season, Caulfield starred in her own short-lived NBC situation comedy, Sally in the role of a traveling companion to an elderly widow, played by Marion Lorne. At midseason, Gale Gordon and Arte Johnson joined the cast. Earlier, in the 1953 and 1954 seasons, she had co-starred with Barry Nelson in the television version of My Favorite Husband.

In 1967 she starred in the western T.V. series The High Chaparral as Annalee Cannon on the pilot episode of the series. She was murdered in the series and that was the premise for the whole plot. In the 1960s and 1970s, Caulfield was active in touring companies of plays, summer stock theater and dinner theater “across the country.” In 1950, Caulfield married the film producer Frank Ross, with whom she had a son, Caulfield Kevin Ross. She and Ross were divorced in 1960. She later married Robert Peterson, a dentist, with whom she had her second son, John Caulfield Peterson. Her second marriage ended in divorce as well. Caulfield died, aged 69, from cancer at Cedars-Sinai Medical Center in Los Angeles, and had lived in Beverly Hills, California. At the time of her death, she had one grandchild. She died within 24 hours of actress Jean Arthur, the first wife of her husband Frank Ross, Jr. Arthur had been married to Ross in 1932, and they divorced in 1949.