The chestnut colt became the second undefeated horse to sweep the Kentucky Derby, Preakness, and Belmont, improving to 6-0 in a racing career that began February 18.
The Mt. Vernon native owns Winstar Farms in Kentucky and has had horses win all three of horseracing's Triple Crown races, just never in the same year.
Despite drawing the rail, Justify went off as a 4-5 favorite and more than lived up to his billing.
Jockey Mike Smith guided the colt to victory for trainer Bob Baffert, who also sent out American Pharoah and is just the second trainer in history to condition multiple Triple Crown winners.
Justify and jockey Mike Smith have drawn gate 1, meaning that it will be an absolute must for the colt to have the same speed he has shown in previous starts, especially during the first quarter-mile. Majority he has already beaten, in either the Kentucky Derby or the Preakness, but there are a few new faces.
After winning the first two races earlier this year, Justify was the clear favourite to win Saturday's race in Elmont, New York. I knew this horse was doing well. The colt named for New England Patriots tight end Rob Gronkowski brings a four-race winning streak into his US debut.
Like "Big Red", as Secretariat was lovingly called, Justify (an even bigger "Big Red", at 16.3 hands and 1,380 pounds, compared to a typical 1,100-pound thoroughbred), broke from the No. 1 post.
"Although he got exhausted (Saturday), he was also looking around a bit at the end", Smith said.
The second-place result was a pleasant surprise for the tight end and his team, given that Gronkowski missed both the Kentucky Derby and the Preakness Stakes due to illness and that the No. 6 horse finished with 24-1 odds to win.
Justify won the Triple Crown's last two stages, the Kentucky Derby and Preakness, last month.