Gillis was born in New Castle, Indiana. He attended New Castle High School and was named an Indiana Junior All-Star following his junior season in which he averaged 21.6 points, 12.2 rebounds, and 2.3 assists per game.[1] However, following a knee injury, Gillis missed the entirety of his senior season.[2]
Gillis was rated a four-star recruit and committed to playing college basketball for Purdue over several other offers including Butler and Xavier.[1]
College career
Redshirt
After missing his senior season in high school with a knee injury, Gillis redshirted in his first season at Purdue.
Freshman season
Gillis appeared in 28 games, with 23 starts. On December 21, 2020, Gillis was named Big Ten Freshman of the Week.[3]
Sophomore season
Gillis started in 25 games of the 33 he played in. He was one of nine players nationally to shoot at least 48% from the field, 40% from 3, and 85% from the free throw line.
Junior season
Gillis played in 32 games, starting in 15. On February 1, 2023, Gillis made 9 3-pointers in a game against Penn State. This was the second most in a single game in Purdue history, behind Carsen Edwards and the most ever in Mackey Arena.
Senior season
Gillis appeared in a school record 39 games, all off the bench. Following the season, he was recognized as the Big Ten Sixth Man of the Year.[4] He also shot 46.8% from 3, which was fifth best for a single season in Purdue history. Gillis's contributions helped Purdue to advance to the 2024 NCAA Tournamentfinal.
COVID eligibility
Despite playing four full seasons at Purdue, Gillis maintained a season of eligibility due to the blanket COVID waiver for the 2020–21 season. On April 26, Gillis committed to Duke to play his final college season.[5]
