Logan Stevenson has acute myeloid leukaemia and has undergone several operations. Last month, doctors said he had only weeks left to live, BBC reported.
This diagnosis prompted Logan's parents, Christine Swidorsky and Sean Stevenson, to bring forward the wedding they had originally planned for July 2014. The wedding was held in Pittsburgh.
Logan was held by his grandmother Debbie Stevenson during the ceremony as he held on to his favourite stuffed rabbit.
"This is our dream come true," a tearful Swidorsky told the Pittsburgh Post-Gazette newspaper.
"It's just going to be one of those things that you remember all your life," Stevenson said.
"It means the world to me. We're just blessed every day that he's here with us," he said.