When the Indianapolis Colts selected an overlooked linebacker out of FCS-level South Carolina State in the second round of the 2018 NFL Draft, critics questioned whether his small-school dominance would translate to Sunday football. Shaquille Leonard spent his entire rookie campaign silencing those doubters, earning the nickname "The Maniac" from teammates for his relentless sideline-to-sideline pursuit and instinctive playmaking that immediately transformed the identity of the Colts' defense.

Leonard’s debut 2018 season stands as one of the most explosive rookie campaigns by a defender in modern pro football history. Pacing the league with 163 combined tackles while adding 7.0 sacks, four forced fumbles, and two interceptions, he captured AP NFL Defensive Rookie of the Year honors and earned First-Team AP All-Pro recognition—a rare feat after being conspicuously snubbed from the Pro Bowl roster. He followed up in 2019 with his first Pro Bowl selection and Second-Team All-Pro honors, proving his rookie performance was no fluke.

Between 2020 and 2021, Leonard solidified his reputation as the sport’s premier turnover-generating off-ball linebacker. He earned First-Team AP All-Pro honors in back-to-back seasons, highlighted by a dominant 2021 masterclass in which he perfected the punch-out technique to lead the NFL with eight forced fumbles, 122 tackles, and four interceptions. His uncanny ability to strip the football in high-leverage moments made him the unquestioned heart and soul of Matt Eberflus' defense.

Tragedy struck in 2022 when a lingering back injury required surgery, cutting his season short after just three games. Upon his return in 2023, lingering nerve issues hampered his signature closing speed, leading to fewer snaps in Gus Bradley's scheme. Frustrated by his diminished role on defense, Leonard was released by Indianapolis midway through the 2023 season and later signed with the Philadelphia Eagles to finish the year.  For the Shoe, Leonard had 614 tackles, 15 sacks, 12 interceptions and 17 forced fumbles.