Sixteen months after the attack killed three people and injured more than 260, including Costello, he married D'Agostino, the nurse who helped him recover. The couple exchanged vows Saturday at the Hyatt Regency Boston in front of about 160 guests.
A photograph of Costello with his clothes ripped to shreds and parts of his body burned became one of the most recognized images of the 2013 attack. He met D'Agostino, a nurse at Spaulding Rehabilitation Hospital, while he was recovering from multiple surgeries for shrapnel injuries and serious burns that required pig skin grafts on his right arm and right leg.
After the couple became engaged, Costello said he believed he was involved in the tragedy in order to meet D'Agostino, whom he described as his best friend and the love of his life.
"One thing that she hates that I always say is I'm actually glad I got blown up," Costello said on the "Today" show in December. "I wish everyone else didn't have to, but I don't think I would have ever met her if I didn't."
Wedding planner Rachael Gross said she and the other vendors involved in the wedding donated their services.
"They are the most gracious, generous, kind, ... loving couple," Gross said. "They believe that they were meant to meet."
The wedding ceremony was held outdoors on the hotel's third-floor terrace, with blue and white hydrangeas all around. The reception was held in the hotel's grand ballroom.
"It was more like a classic Nantucket style, but without a literal nautical theme," Gross said.
Costello, of Malden, was gathered with friends near the marathon finish line, watching for another friend who was running when two bombs exploded within seconds of each another. Three of Costello's friends lost a leg, while other friends suffered burns and shrapnel injuries.
During his two-week stay at Massachusetts General Hospital, Costello was among patients who met President Barack Obama. He was later transferred to Spaulding.
Costello and D'Agostino, both 31, are honeymooning in Hawaii.
[caption id="attachment_59319" align="alignnone" width="300"] In this April 15, 2013, file photo, provided by The Daily Free Press and photographer Kenshin Okubo, Boston Marathon bombing victim James Costello staggers away in his torn clothing from the finish area in Boston. Costello married Krista D’Agostino Saturday, Aug. 23, 2014 ,at a hotel in Boston. The couple met at Spaulding Rehabilitation Hospital where D’Agostino worked as a nurse and helped him recover from his burns and injuries. (AP Photo/The Daily Free Press, Kenshin Okubo, File)[/caption]