Mr Obama was lifted in a bear hug by 1.90m-tall (6.2ft) pizza shop owner Scott Van Duzer during a bus tour.
“Scott, let me tell you, you are like the biggest pizza shop owner I’ve ever seen,” said the president.
“I don’t vote party line, I vote who I feel comfortable with, and I do feel extremely comfortable with him,” the 46-year-old owner of the Big Apple Pizza in Fort Pierce said.
He added that he rushed to embrace the president because he was “overcome with excitement”.
Mr Van Duzer also runs a community blood donation operation, prompting Mr Obama to say he had “a big heart, along with big pecs”.
Mr Van Duzer told BBC News that Mr Obama had stayed for about 20 minutes, and that it had been a great meeting.
The president ordered 20 pizzas and paid with cash, he said.