Lamarr was born in Vienna, Austria-Hungary, and acted in a number of Austrian, German, and Czech films, including the controversial Ecstasy (1933). After this brief early film career, she fled from her husband, a wealthy Austrian ammunition manufacturer, and secretly moved to Paris in 1937 and then onward to London. There she met Louis B. Mayer, head of Metro-Goldwyn-Mayer (MGM) studio, who offered her a movie contract in Hollywood, where he began promoting her as the "world's most beautiful woman".

She became a star with her performance in Algiers (1938), her first film made in the United States. Her other MGM films include Lady of the Tropics (1939), Boom Town (1940), Come Live with Me and H.M. Pulham, Esq. (both 1941), and White Cargo (1942). Dismayed by often being typecast, Lamarr co-founded a new production studio and starred in its films: The Strange Woman (1946), and Dishonored Lady (1947). Her greatest success was as Delilah in Cecil B. DeMille's Samson and Delilah (1949). She also acted on television before the release of her final film, The Female Animal (1958). She was honored with a star on the Hollywood Walk of Fame in 1960.

At the beginning of World War II, Lamarr and composer George Antheil developed a radio guidance system for Allied torpedoes, intended to use frequency-hopping spread spectrum technology to defeat the threat of jamming by the Axis powers. She also helped improve aviation designs for Howard Hughes while they dated during the war. Although the US Navy did not adopt Lamarr and Antheil's invention until 1957, various spread-spectrum techniques are incorporated into Bluetooth technology and are similar to methods used in legacy versions of Wi-Fi. Recognition of the value of their work resulted in the pair being posthumously inducted into the National Inventors Hall of Fame in 2014.