Maximum Security had "unspecified physical issues" as a two-year-old and did not make his first start until December 20, 2018, in a maiden claiming race. He won in commanding fashion by lengths. In that race, he could have been claimed for $16,000, but fortunately for the Wests was not.
Three-year-old season Maximum Security began his three-year-old campaign by winning two starter optional claiming races at
Gulfstream Park in early 2019, both of them over sprint distances, by a combined distance of lengths. He was then stepped up in both class and distance when entered in the Grade I
Florida Derby at a distance of miles on March 30. Maximum Security went to the early lead and set a reasonable pace, trailed by longshot Bodexpress. He was never challenged and won by lengths, with favorites Hidden Scroll and Code of Honor well back. Maximum Security earned 100 points on the
2019 Road to the Kentucky Derby, instantly qualifying him for the Kentucky Derby. Maximum Security was the first horse to cross the finish line first in the Kentucky Derby only to be disqualified for an on-track infraction. The only other winner to be disqualified in the Kentucky Derby up until that point in time had been
Dancer's Image, who was disqualified in 1968 for a drug infraction. The disqualification was controversial, especially in the Derby which is often a roughly run race due to the large field. Jockey
Luis Saez said the horse had shied away from the noise of the infield crowd, but was immediately brought under control. Maximum Security did not materially affect Country House, who was awarded the victory. However, his swerve did affect several other horses and could have caused a major accident if he had clipped heels with another horse. Saez was subsequently suspended for 15 days for "failure to control his mount". On May 14, 2019, the owners of Maximum Security sued in
U.S. District Court in
Frankfort, Kentucky, seeking to reinstate the win and distribute purse money based on the actual order of finish. On June 8, the
Kentucky Horse Racing Commission filed a motion requesting dismissal of the lawsuit, stating that it "threatens to turn the 'most exciting two minutes in sports' into tedious, protracted litigation." In November 2019, the lawsuit was dismissed, citing "the stewards’ decision in determining fouls and disqualifications of horses is final and not subject to appeal".
Post-Derby races Maximum Security's owners chose not to enter him in the
Preakness or the
Belmont. He returned to the track on June 16, when he was made
1-20 favorite for the
Pegasus Stakes at
Monmouth Park, but sustained an upset defeat as he was beaten by a length by King for a Day. On July 20, Maximum Security was entered in the
Haskell Invitational Stakes at Monmouth Park, going off as the 4-5 favorite in a field of six. He rated in third behind the early pace set by Bethlehem Road and King for a Day, tracked by Mucho Gusto. Around the far turn, first Bethlehem Road and then King for a Day dropped back, leaving Maximum Security and Mucho Gusto to battle for the lead. At the eighth pole, Maximum Security was a head in front but Mucho Gusto appeared to have the momentum. Maximum Security rallied and drew away to win by lengths. He then faced a stewards' inquiry after he appeared to bear in slightly on the far turn when King for a Day started to tire. However, the stewards ruled that there was no cause for disqualification. The win moved Maximum Security back into contention for champion three-year-old honors. However, he missed a planned start in the Travers Stakes because he was not training up to expectations. "I don't like where he's at," said Servis on August 15. "He's not eating the way I want him to eat, and he's not carrying the weight I'd like to see him carry." He was next entered in the
Pennsylvania Derby, but was scratched 5 days before the race due to a large colon nephrosplenic entrapment. He was rushed to the Mid-Atlantic Equine Clinic where he was diagnosed with
colic. "He just got his [colon] displaced tightly enough that it was extremely painful," said Gasiorowski. "He was sent to our clinic immediately and we managed to get him to correct without doing surgery." His connections gave him time to recover, and ruled out his participation in the
2019 Breeders' Cup. They instead entered him in the
Bold Ruler Handicap on October 26, which he won in front running fashion by lengths. "I knew we were going to get criticized for running in a Grade III race by ignoramuses who don't know that after a horse has colic and is off for three months, you don't want to start him at a mile and a quarter," said West. "But I'm immune to that. Jason knows the right thing to do with the horse, and I know the right thing to do with the horse." Maximum Security finished his three-year-old campaign by winning the Cigar Mile Handicap on December 7 at
Aqueduct Racetrack as the 6-5 favorite. His main rival was considered to be Spun to Run, who had won the
Breeders' Cup Dirt Mile. Maximum Security went to the early lead and was soon joined by Spun to Run. The two raced together for the first three-quarters of a mile until Maximum Security started to pull away at the head of the stretch. He won by lengths in a time of 1:36.46. Gary West told
The Blood-Horse in December 2019 that he was keeping the horse in training for 2020. He was leaning towards running Maximum Security in the inaugural
Saudi Cup, to be held on
King Abdulaziz Racetrack in
Riyadh,
Saudi Arabia on February 29. He had initially considered the
Pegasus World Cup at Gulfstream Park in January, but ruled that out after it was announced that its purse would be cut from $9 million to $3 million. Maximum Security was named the
American Champion Three-Year-Old Male Horse at the 49th annual
Eclipse Awards with 217 out of 241 votes. "It's a special honor for Mary and me," said Gary West. "It will not make up for what happened in the Kentucky Derby, but it's a nice way to close the year."
Four-year-old season On January 1, 2020, it was announced that
Coolmore Stud had purchased a 50% share in Maximum Security. Maximum Security was shipped to Saudi Arabia in February 2020 for the inaugural $20 million
Saudi Cup, run on February 29 over a distance of nine furlongs. The field contained multiple Grade/Group One winners from around the world including
Midnight Bisou (American Champion Older Female Horse),
Mucho Gusto (2020
Pegasus World Cup winner),
Benbatl (2019
Caulfield Stakes winner),
McKinzie (2019
Alysheba Stakes and 2019
Whitney Stakes winner), Chrysoberyl (undefeated 2019
Japan Dirt Derby winner), and Gold Dream (2017
Champions Cup winner). Capezzano set the early pace, followed closely by Mucho Gusto with Maximum Security tracking them a few lengths behind. Mucho Gusto moved to the lead as they entered the far turn, then swung very wide as they entered the stretch. Maximum Security, who had started his move on the outside, switched paths and started to make up ground. He passed Mucho Gusto with about 100 yards remaining, then held off Midnight Bisou, who made a late run along the rail. "It was a tough race but we did it," said Saez. "For a second I thought we were going to be beaten but he has such a big heart. He's the toughest horse I've ridden." After Servis was indicted in March for doping allegations, Maximum Security was transferred to the barn of Bob Baffert. He was given an extensive exam that revealed some minor lameness but no serious long-term damage. He was given a layoff to recover and also to ensure that any drugs were cleared from his system, then resumed galloping on April 29. He made his first start for Baffert in the
San Diego Handicap at
Del Mar on July 25, carrying top weight of 127 pounds. He took the early lead around the first turn but was then challenged by Midcourt as they moved into the backstretch. Maximum Security dropped back then shifted to the outside around the final turn and started to make up ground. Midcourt fought back and the two horses dueled down the stretch, with Maximum Security winning by a neck. "I knew I didn't have him really drummed up for this race," said Baffert. "He won today when he had every reason to get beat. He showed what a great horse he is today." His next start was the
Pacific Classic Stakes at Del Mar Racetrack, where he was the 2-5 favorite in a field of six that included Higher Power, who had won the race in 2019, and multiple graded stakes winners Midcourt and Sharp Samurai. Maximum Security broke sharply and set a moderate pace of :23.93 for the first quarter-mile and :47.98 for the half. When Sharp Samurai and Higher Power tried to challenge him on the final turn, he responded. Nearing the quarter pole he began to edge away from Sharp Samurai, and won going away by lengths. This gave him an automatic berth into the
Breeders' Cup Classic. On September 26, he raced in the 2020
Awesome Again Stakes. This was a highly anticipated match up between Maximum Security and his stablemate
Improbable, who had won the Grade 1
Hollywood Gold Cup and Grade 1
Whitney Stakes earlier in the year. Maximum Security stalked the pace set by Take The One O One, until the far turn, when Improbable rallied from last to take the lead. Maximum Security briefly tried to engage his stablemate, but he couldn't match Improbable and finished in second place. In the
Breeders' Cup Classic on November 7 in
Keeneland he was one of the favorites, but he lost ground in the last corner and finished fifth. His stablemates
Authentic and
Improbable finished 1st and 2nd. == Racing statistics ==