Ridden by jockey Jeremy Rose, Afleet Alex used a mighty surge down the final quarter-mile of the 1 ½-mile oval track to handily take the season's third and final event in horse racing's Triple Crown.
Andromeda's Hero finished a distant second, while Nolan's Cat placed third.
Giacamo, the surprise 2005 Kentucky Derby champion, was seventh.
Afleet Alex, ridden by jockey Jeremy Rose, approaches the finish line at the 137th Belmont Stakes Saturday in Elmont, N.Y.. (AP Photo/Bill Kostroun)
Afleet Alex is just the 11th thoroughbred to win the Belmont and Preakness after running in the Kentucky Derby. Point Given was the last horse to achieve the feat, winning both races in 2001.
Installed as a 6-5 favourite after winning the 130th Preakness Stakes three weeks ago in Baltimore, Afleet Alex trailed for much of Saturday's race.
Afleet Alex dropped back from the start, as longshot Pinpoint paced the field in the early stages. Giacamo made a move midway through the race and appeared to be the horse to beat, but Afleet Alex used the remarkable late push to take the title.
Afleet Alex endeared himself to horse racing fans after a breathtaking effort in the Preakness.
The champion almost tumbled to the track after clipping heels with another horse. However, Afleet Alex and Rose averted disaster, displaying athleticism and balance in remaining upright and going on to win the race in stunning fashion.
Afleet Alex earned $600,000 US for Saturday's triumph, his eighth victory in 12 races.
with files from Canadian Press
