Charles Coughlin, better known as Father Coughlin was a Roman catholic priest and political leader in the 1930s. He had an extremely popular radio show that reached as many as 30 million listeners. At first a vocal supporter of Roosevelt and The New Deal, he soon changed after claiming Roosevelt was too nice to the "Jewish" Bankers. He began to use his radio show as a way to issue antisemitic commentary, as well as to support the policies of Adolf Hitler and Benito Mussolini. He also claimed they were the antidote to communism. After the outbreak of WW2 the Roosevelt administration eventually force the cancellation of his radio show.

A few of his speeches can be found on Youtube, but I'm not sure if I'm allowed to link them.

Hopefully this helped a little, I'm not a Historian but I hope I answered your question.

There were a number of prominent Americans with political influence and/or connections who were very friendly towards the Nazis. One of the most notable was Charles Lindbergh, who used his influence to urge the U.S. take a neutral stance to Nazi Germany. He was strongly antisemitic, though he saved his greatest vitriol for private correspondence. Shortly after Krystallnacht, he decided to move TO Germany, even though Krystallnacht was an event that caused most others to turn firmly against Germany. He met Hitler and accepted a medal from him. He became friends with Henry Ford, a notorious Nazi sympathizer and anti-Semite (Hitler had a photo of Ford in his office, while Ford bought a newspaper and used it to translate and publish lots of antisemitic stuff that the Nazis liked. Lindbergh published a book and sent signed copies to all the members of congress (Lindbergh's father had been a congressman, FYI). The book urged neutrality. If you want a copy of it, signed copies are always on the rare book market, each inscribed to a politico of the day. As US sentiment turned increasingly against Germany, Americans turned increasingly against Lindbergh. He resigned his military position, and was shunned for awhile. Rumors were that he was a Nazi spy. Katherine Hepburn and Spencer Tracy starred in a film that was loosely inspired by these events. Hepburn is married to a Lindbergh-esque guy who IS an enemy agent who is running for president and planning to reveal his nefarious side once he is elected.

Then there's Joseph Kennedy Sr., father to JFK and RFK. He was an ambassador, and had serious Nazi sympathies.

If you want to read more, I recommend Hitlerland, a book about Germany and Hitler in the 1920s and 30s, focusing on what Americans thought of Hitler, the Nazis, and Germany in the early days of the 3rd Reich and Hitlers climb to power. And then there's in the Garden of Beasts, about the US ambassador to Germany from 1933-35, appointed right after FDR and Hitler became leaders of their respective nations. He--Ambassador Dodd--was initially pleasantly surprised at the new Germany. His beautiful young daughter Martha was utterly captivated and immediately started dating and partying with top officials in the Nazi party. But a slow and dawning horror overtook them as they realized the true nature of what they were in the midst of. In Hitlerland, the author describes 4 stages that American expats in Nazi Germany went through when they arrived in Berlin. At first there was elation at how great it was. Then questioning, then disgust, then horror. You Can read more details about your questions there. It's also fair to say that while there weren't all that many Americans who liked the Nazis, a lot were simpatico regarding antisemitism, and the U.S. embassies almost entirely cut the visas they gave out to Jews, such that at no time during the Hitler years did the U.S. even come close to giving out as many visas to Jews to the U.S. as they had a quota for.