Justwhistledixie was a descendant of the American broodmare Bold Irish who was the female line ancestor of numerous major winners including Ruffian, Pine Bluff and Fusaichi Pegasus.

[5] In September 2014 the yearling was consigned to the Keeneland sales and was bought for $2.2 million by Hamdan Al Maktoum's Shadwell Estate Co.[6] The colt was sent into training with Kiaran McLaughlin.

The colt was then stepped up sharply in class for the Grade II Nashua Stakes over one mile at Aqueduct Racetrack on November 4.

Starting the 11/10 favorite he moved up on the outside to dispute the lead on the final turn, gained the advantage early in the stretch and won by one and three quarter lengths from Flexibility despite drifting to the right in the closing stages.

After tracking the leader Donegal Moon, he moved into contention on the final turn, took the lead a furlong out and won by one and a half lengths from Flexibility.

[10] In the early part of 2016, Mohaymen was sent to race in Florida and was based at the Palm Meadows Training Center in Boynton Beach.

[13] In the highly anticipated matchup, Nyquist won the Florida Derby by 3+1⁄4 lengths, defeating rival Mohaymen, who "did not fire" and finished fourth.

After racing in mid-division he was switched to the outside and made steady progress in the straight to finish fourth behind Nyquist, Exaggerator and Gun Runner.

[15] Monhaymen was given some time off then returned to racing on July 30 in the Jim Dandy Stakes, where he finished fourth after stumbling at the break.