2023: two-year-old season Sierra Leone made his debut on November 4 in a maiden special weight event over 1 mile at
Aqueduct Racetrack. He broke from post 5, bobbled at the start, was roused three wide on the turn, came five wide into upper stretch, and won with
Manuel Franco aboard by one and one-quarter lengths in a time of 1:36.94.
2024: three-year-old season On February 17, 2024, Sierra Leone began his three-year-old campaign in the Grade II
Risen Star Stakes at
Fair Grounds Race Course in
New Orleans. Starting as the 2/1 favorite, he was unhurried early on and uncorked a winning rally in the stretch, prevailing by a half-length in the -mile event. As a result of his wins in the
Risen Star Stakes and
Blue Grass Stakes, Sierra Leone finished first in the qualification standings in the
Road to the Kentucky Derby and entered the
Kentucky Derby as one of the favorites. On June 8, 2024, the
Belmont Stakes was held at
Saratoga Race Course due to renovations at
Belmont Park, with the distance dropped from the usual miles to miles. Sierra Leone entered the race as the 9-5 favorite following his narrow second-place finish in the
Kentucky Derby. Under jockey
Flavien Prat, he finished third, 1½ lengths behind the winner,
Dornoch. Returning to
Saratoga Race Course on July 27 for the Grade 2
Jim Dandy Stakes, Sierra Leone trailed in last place early, then made a significant move around the final turn. After a strong inside run, he finished second, one length behind
Fierceness. On August 24, Sierra Leone competed in the Grade 1
Travers Stakes at Saratoga at the 1¼-mile distance. He was far back to start as usual before launching a bid in the stretch. Ultimately, he secured a third-place finish, with
Fierceness taking the victory and filly
Thorpedo Anna finishing second. On November 2, 2024, Sierra Leone won the
Breeders' Cup Classic, defeating two-year-old champion
Fierceness by 1 ½ lengths. After starting near the back of the field, he took advantage of a fast early pace and unleashed a late kick to prevail in a final time of 2:00.78.
2025: four-year-old season In the Grade II New Orleans Classic on March 22, 2025, at
Fair Grounds. Sierra Leone, the reigning champion 3-year-old male, finished third. The race was won by Touchuponastar, a Louisiana-bred gelding, who led from start to finish, winning by 2½ lengths over Hall of Fame, with Sierra Leone trailing by 8½ lengths. This unexpected result marked a setback for Sierra Leone in his 4-year-old debut. On June 28, 2025, Sierra Leone competed in the Grade 1
Stephen Foster Stakes. After settling back early, Sierra Leone unleashed a strong late surge and consistently trailed the front-runners before making up ground in the final furlongs. His effort held off the rest of the field but couldn't quite catch
Mindframe down the lane. This performance reaffirmed his elite form and status among America's top older horses. After a shaky start to his 4-year-old season, Sierra Leone delivered a sensational performance in the
Grade I Whitney Stakes on August 2, 2025, at
Saratoga. The Chad Brown trainee unleashed his trademark late surge to rally from last and defeat a strong field that included
Fierceness and
White Abarrio. ==Stud==