After an early and brief film career in Germany, which included a controversial film Ecstasy (1933), Lamarr fled from her husband, a wealthy Austrian ammunition manufacturer and secretly moved to Paris. There, she met MGM head Louis B. Mayer, who offered her a movie contract in Hollywood, where she became a film star from the late 1930s to the 1950s.

Lamarr appeared in numerous popular feature films, including Algiers (1938), I Take This Woman (1940), Comrade X (1940), Come Live With Me (1941), H.M. Pulham, Esq. (1941), and Samson and Delilah (1949).

At the beginning of World War II, Lamarr and composer George Antheil developed a radio guidance system for Allied torpedoes, which used spread spectrum and frequency hopping technology to defeat the threat of jamming by the Axis powers. Though the US Navy did not adopt the technology until the 1960s, the principles of their work are now incorporated into modern Wi-Fi, CDMA, and Bluetooth technology, and this work led to their being inducted into the National Inventors Hall of Fame in 2014.