Lamarr wanted to join the National Inventors Council but was told that she could better help the war effort by using her beauty and celebrity status to sell war bonds during WWII. Once again her gender and beauty dictated her roles, so she participated in a bond campaign with a sailor, traveling to 16 cities in 10 days, selling $25 million in war bonds. Lamarr also started an MGM campaign that generated 2,144 letters to servicemen, while signing autographs at the Hollywood Canteen for off duty soldiers.

"We began talking about the war, which, in the late summer of 1940, was looking most extremely black. Hedy said that she did not feel very comfortable, sitting there in Hollywood and making lots of money when things were in such a state. She said that she knew a good deal about munitions and various secret weapons ... and that she was thinking seriously of quitting MGM and going to Washington, DC, to offer her services to the newly established National Inventors Council."

-George Antheil, 'Beautiful: The Life of Hedy Lamarr', 2010 

“America has been attacked. The USS Kearny is not just a Navy ship. She belongs to every man, woman, and child in this nation … All of us Americans, of all opinions, are faced with the choice between the kind of world we want to live in and the kind of world which Hitler and his hordes would impose upon us."

-President Franklin D. Roosevelt, “Navy and Total Defense Address,” October 27, 1941

During WWII, the Allies were plagued by German U-boat torpedo attacks. Therefore, they needed the ability to transmit messages within the military in secrecy. This forced allies and enemies to develop their own various forms of encrypted electronic communications. When the Germans developed the new enigma machine, they thought it was completely undecipherable. Lamarr, an immigrant from Austria told the U.S. government everything she knew about Hitler, as her first husband, Mandl, provided weapons to Mussolini and Hitler.​​​​​​​ Yet, this caused the U.S. military to not trust her at first.​​​​​​​

Richard Rhodes, "Hedy Lamarr: Hollywood Star & Inventor", The Henry Ford's  Innovation Nation, 2015