'Go! Go!' agents shouted as they whisked Trump away and a combination of local police and private security wrestled Austyn Crites, 33, to the ground in the front of the crowd.
Mr Crites identifies as a Republican who supports Democratic presidential candidate Hillary Clinton, according to his Facebook page.
A Trump campaign official told Daily Mail that the suspect, whom rally-goers already identified as an anti-Trump protester, caused a panic when he reached into his waistband.
At that point, the campaign official said, a voice called out: 'He's got a gun!'
Trump's protective detail sprang into action, pulling him offstage as a sea of bodies scattered, screams rang out and authorities dragged Mr. Crites away as he kicked and strained.
U.S. Secret Service said in a statement that 'a commotion' had occurred 'in the crowd immediately in front of the stage' and 'an unidentified individual shouted, "gun".'
The man has been cleared and released.