America had Lindbergh, the guy who was first to cross the Atlantic in a plane. Back around 1940, he did a lot of pro-Nazi things like push the "America First" initiative who's purpose was to keep America neutral during the war.
Einstein gave Lindbergh a letter to deliver to President Roosevelt explaining the threat of nuclear fission. Lindbergh didn't deliver it.
Lindbergh was an anti-Semite, saying things like Hitler was saving Europe from a Jewish takeover.
Lindbergh is the most famous American I can think of. There are lots of not famous Americans who were pro-Nazi. We even had a Nazi party, but it disbanded when the war started.