[6] To ease congestion at Belmont Station from racing fans leaving the venue, which led to hours-long waits the previous year, the Long Island Rail Road invested $4 million to improve mass transit in the area, and the New York Racing Association put in another $1 million.

[7] On May 29, 2015, the NYRA announced that the daily fantasy sports service DraftKings had acquired presenting sponsorship rights to the race.

[8] Two weeks before the event the connections for several horses announced that they would be entering the race after bypassing the Preakness Stakes.

These included the following participants of the 2015 Kentucky Derby: Frosted, who finished fourth; Materiality, sixth; Keen Ice, seventh; Mubtaahij, eighth; Carpe Diem, tenth; Frammento, eleventh; and War Story, who was sixteenth.

[9] When the field was ultimately drawn for the race on June 3, Carpe Diem and War Story were not entered.

The exception was Madefromlucky, who won the Peter Pan Stakes and had last faced American Pharoah in the Arkansas Derby.

[19] Of the group, Frosted, who ran wide on the turn in the Kentucky Derby but rallied strongly to finish fourth, just three lengths from the lead, was considered by some commentators to pose the strongest challenge to American Pharoah.

Keen Ice ran in the middle of the pack until a late rally brought him into third over Mubtaahij, who was fourth.

American Pharoah crossed the finish line leading by 5+1⁄2 lengths, with a winning time of 2:26:65 for the 1+1⁄2-mile (2,400 m) race, the second fastest among Triple Crown winners.