He wanted to send a message.
"I was thinking that I could get up on stage and take his podium away from him and take his mic away from him and send a message to all people out in the country who wouldn't consider themselves racist, who wouldn't consider themselves approving of what type of violence Donald Trump is allowing in his rallies, and send them a message that we can be strong, that we can find our strength and we can stand up against Donald Trump and against this new wave he's ushering in of truly just violent white supremacist ideas," DiMassimo told CNN.
But DiMassimo, 22, didn't make it to the podium.
He was quickly blocked by Secret Service officers, and members of Trump's security detail rushed to cover him. After a few moments, the GOP front-runner, who was visibly startled, gave a thumbs-up and thanked the cheering crowd for warning him.
DiMassimo, 22, of Fairborn, Ohio, was arrested and charged with disorderly conduct and inducing panic. His next court date is Wednesday. The Wright State University senior sat down with CNN on Sunday to talk about what he did and why.
"I was thinking that Donald Trump is a bully, and he is nothing more than that. He is somebody who is just saying a lot of bold things, he's making bold claims. But I can see right through that and I can see that he's truly just a coward. And he's opportunistic and he's willing to destroy this country for power for himself," DiMassimo said.
When asked whether he'd planned on attacking Trump if he'd been able to reach him, DiMassimo said he had not.
"No, not at all. There would have been no point. Donald Trump is 6 foot 3. I'm 5 foot 9, maybe. He's a giant man surrounded by thousands of followers, 12 Secret Service and a former Ohio State offensive lineman. That would have accomplished nothing."
He said he could understand, though, how people might have perceived he was planning to attack Trump, and that he hadn't expected so many Secret Service officers.
"I thought my chances of getting up on stage and getting to the podium would have been better," DiMassimo said.
"But again it was more important for me to show that there are people out there who aren't afraid of Donald Trump. He says scary things. He lets his people do scary things. He's threatened Mexico, Islam, you name it, and yet I'm unafraid. And if I can be unafraid enough to go take his podium away from him, then we all can be (un)afraid enough to not let this man walk into the White House."
When asked who he voted for, DiMassimo said he voted for Democratic candidate Bernie Sanders. He voted in Georgia. DiMassimo said several times his support for Sanders did not prompt the stunt.
'Not a member of ISIS'
After his rally, Trump tweeted about the incident, thanking his security and accusing DiMassimo of having ties to ISIS.
"USSS did an excellent job stopping the maniac running to the stage. He has ties to ISIS. Should be in jail!" Trump wrote.
He posted a link to a video that included the ISIS flag and appeared to make fun of DiMassimo.
DiMassimo vehemently denied belonging to ISIS. He told CNN the video was doctored and provided a link to what he said was the original footage from a protest he participated in more than a year ago.
Trump responded to criticism of his tweet Sunday on NBC's "Meet the Press."
"Was that him? It looked like the same man to me. He was dragging a flag along the ground and he was playing a certain type of music. And supposedly, there was chatter about ISIS. Now, I don't know. What do I know about it? All I know is what's on the Internet," he said. "And I don't like to see a man dragging the American flag along the ground in a mocking fashion."
DiMassimo said he's received thousands of death threats since the Trump rally and that his parents have also been threatened.
When asked whether he was a Christian, he said he was.
"I am not a member of ISIS. I have no known ties to ISIS. I've never been out of the country. I only speak English," DiMassimo said.