Joan Weldon was lucky enough as an actress to get in briefly at the end of the Hollywood studio system, make some good movies (and one great one), and then land on her feet in musical theater, which is where she wanted to be in the first place. Born Joan Louise Welton in San Francisco, she was the daughter of a prominent attorney. As a child, she showed a keen interest in music and studied piano and voice. She joined the chorus of the San Francisco Grand Opera Company and later sang with the Civic Light Opera Company. It was during a performance with the latter that she was spotted by screenwriter-turned-producer Stanley Rubin (Macao, The Narrow Margin, River of No Return), who arranged for her to have a screen test at 20th Century Fox. The studio passed on her, however, because it wasn't in the market for vocalists. Meanwhile, she appeared on television as a singer on the series This Is Your Music and later crossed paths with William T. Orr, the son-in-law of Warner Bros. co-founder Jack L. Warner (and later the executive in charge of the company's television division), which led to a contract with Warners. Her last name was changed to Weldon and she narrowly missed out being cast as a victim of Vincent Price's malevolence in André De Toth's 3-D horror classic House of Wax. Instead, her contribution to the 3-D movie craze was as the second female lead in De Toth's The Stranger Wore a Gun amid a cast that included veterans Randolph Scott, Claire Trevor, and George Macready and future stars Ernest Borgnine and Lee Marvin. Weldon was also loaned out to MGM in the Sigmund Romberg bio-musical Deep in My Heart (1954), and ended up cut from the picture for her trouble.
Weldon was cast in a series of Westerns, including The Command and Riding Shotgun, but her greatest contribution to the screen was as the female lead in Gordon Douglas' Them! The first and best of Hollywood's radioactive/giant monster movies, the film relied more on characters than most others in the genre and featured an extraordinary cast, including one Oscar-winner (Edmund Gwenn), one Oscar-nominee (James Whitmore), one future TV star (James Arness) in the lead, and another two (Fess Parker and Leonard Nimoy) in small roles. Weldon broke some cinematic ground, playing a notably intelligent and assertive female character who also happened to be beautiful. "We took the movie very seriously," she recalled in a 2004 interview, "exactly like any other drama." Of her co-star Edmund Gwenn, she said, "He was the sweetest man, and he was quite elderly by then and riven with arthritis, but he worked as hard as any of us; when the director called 'Action,' he did everything asked of him, all of the climbing and the walking through the desert. It was just that, when they called 'Cut!,' he had a manservant that would rush over to him and get him to a chair." Weldon's career in movies ended with the expiration of her Warner Bros. contract in 1954. She resumed her singing career with Jimmy McHugh and was later in the road company production of The Music Man, playing Marian Paroo. Weldon made her way to Broadway in Kean, starring opposite Alfred Drake, and opened the State Theatre at Lincoln Center in New York playing opposite John Raitt in a scene from Carousel. She later toured with Fess Parker in Oklahoma and, in 1967, played the lead in a production of Franz Lehar's The Merry Widow at Lincoln Center. Weldon retired from the stage in 1980, but was still well remembered by opera and musical fans in the early 2000s. She also attracted a crowd when she turned up as a member of the audience in March 2004 at a rare 3-D screening of The Stranger Wore a Gun in New York.