The 38-year-old became the first American to win the race since 1983 by completing the 26.2-mile course in a time of two hours, eight minutes, 37 seconds.
Keflezighi got a big hand from the crowd, waved to them, tipped his hat and then fired a pitch to Jonny Gomes. Keflezighi was wearing a Boston Strong hat and a Red Sox jersey that had 26.2 on the back.
Quinn Roberts is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.