The 25-year-old Crews completed the 26.2-mile course in 2 hours, 17 minutes, 15 seconds. Brian Clas of New York was the last U.S. man to win the race.
"I thought if I had a good day I would be up there," said Crews, a native of Lexington, Va., who lives in Raleigh, N.C.
Jutta Merilainen won the women's event in 2:46:44. She beat Doreen McCoubrie of Malvern, Pa., who finished in 2:49.09.
The 37-year-old Merilainen, a native of Finland who lives and trains near Toronto, started to think she had a shot at winning about halfway through the race. She ended up with a personal best time.
"This was my biggest win so far," she said.
Crews passed Philadelphia runner Karl Savage near the 23-mile mark and was never threatened afterward. Crews' 2:17:15 gives the native of Lexington, Va., an automatic qualifying time for the 2012 U.S. men's Olympic marathon trials.
After the race, he thanked his fiancee, Amy Kelly, who hails from Philadelphia and finished third in Sunday's accompanying 8-kilometer race. Her family was out cheering them both. "They were all out on the course cheering for me," Crews said. "They're all from Philadelphia, so it was nice to get the win in front of them. It's just starting to sink in."