Brady Garrett, 25, was holding up signs during the rally that said "Research Holocaust Revisionism" and "1488," the latter of which is a combination of numbers emblematic of Nazism and white supremacy. He was escorted out of the event by Trump security.
Talking to reporters after the rally, Garrett said the United States needs "to put European Americans first" and disparaged Zionists.
Garrett confirmed that he was a neo-Nazi and disputed facts about the Holocaust. When asked if he thinks espousing such views at a Trump rally could hurt the Republican nominee, he said, "No."
"We need to speak the truth," he said, adding that he doesn't "give a damn" about any of Trump's policies and only supports him because he's "anti-establishment."
Meanwhile, a couple dozen Trump supporters started circling him and yelling out pro-Trump chants to try and drown him out. Others flat-out confronted him and the reporters who were interviewing him.
"Why are you trying to speak for everybody? You go speak for somebody else," Robert Santos or Reno shouted at Garrett.
"The guy's a nut job," Santos later told CNN. Asked if it bothers him that someone like Garrett supports Trump, Santos said, "It bothers me anywhere that they support anybody. It's their right but we don't need to interview that person."
One woman got in front of the cameras.
"I don't care what color people are if they love America," she said. "This guy is an idiot!"
Another woman, Carleen Reich Simko, said "there were so many thousands of other people here without this white supremacy label."
Garrett was wearing a shirt with the label for the State of Jefferson, a secession movement in California.
A disabled veteran, Joe Turner of Milford, California, also identified as a State of Jefferson supporter but said he was "pissed off" at Garrett for wearing that shirt while advocating Nazism at the same time.
"We do not support that garbage at all," Turner said, visibly upset at the incident.