Duane Hammond says it's what got him fired.
Hammond is a union stagehand who was part of the crew that built the platform for the Obama event on campus.
Hammond's son is in the Navy, currently serving on the aircraft carrier U.S.S. George H. W. Bush.
Hammond says he was not trying to make a political statement.
He says he got the sweatshirt and hat during a visit to the aircraft carrier on Family Day.
The back of his sweatshirt has a large drawing of the ship.
He says he wore it to show how proud he is of his son.
That didn't go over well with his union supervisor.
Hammond says he was told to take off the sweatshirt, or he would have to go home.
He refused. They told him he was fired from the job.
James Wright, a business representative from IATSE Local 33, says the union is still investigating what happened.
"If he was sent home because of the sweatshirt, he will be paid for the day," he said.