He previously played college basketball for the Cincinnati Bearcats, where he was a two-time Third-team All-AAC performer, as well as for the Michigan Wolverines.

[10] On November 10, 2017, DeJulius tendered his National Letter of Intent as part of a five-man recruiting class that included Ignas Brazdeikis, Colin Castleton, Brandon Johns, and Adrien Nunez.

Then, DeJulius had 25 points in the second half, including 17 in the fourth quarter, against the defending 2017 Michigan High School Athletic Association Class A state champions,[17] who would repeat in 2018.

[27] By the end of the season, DeJulius was behind Zavier Simpson and his backup Eli Brooks on the depth chart for head coach John Beilein.

[32][33] On May 22, 2019, Juwan Howard signed a five-year contract as the head coach of the Michigan Wolverines men's basketball team.

[36] During the Michigan Wolverines' 2019–20 season, DeJulius played as a sophomore alongside starting guards Simpson and Brooks as well as Franz Wagner.

Serving in a sixth man role, he averaged 7.0 points, 2.4 rebounds, and 1.5 assists in 20.9 minutes per game coming off the bench.

[53][55] On February 25, 2021, he became the fifth member of the 2020–21 Cincinnati Bearcats to opt out of the rest of the 2020–21 NCAA Division I men's basketball season due to the mental impact of COVID-19.

[56] Within two days after the March 14, 2021 American Athletic Conference men's basketball tournament championship game loss to Houston, the Bearcats saw six players enter the transfer portal.

[64] On February 24, 2022, he announced that he would not partake in Senior Night fanfare, in part because he was eligible to return with another year due to special COVID-19 waiver.

[65] DeJulius earned third-team All-American Athletic Conference as a true senior for the 2021–22 Cincinnati Bearcats men's basketball team.

[68] Before the season, he announced that he would donate his student athlete compensation proceeds from his team-licensed jersey sales to provide books to inner city youth in Detroit and Cincinnati.

[69] He began the season by leading the 2022–23 Cincinnati Bearcats to three victories, averaging 21.3 points and 3.7 assists while shooting 56.1% from the field, including 7-of-9 on three-point shots, and earning American Athletic Conference player of the week honors.

[70] When DeJulius was honored on March 5, 2023 Senior Night, along with Kalu Ezikpe and Rob Phinisee prior to the game against SMU, he posted a career-high 30 points with 6 assists.

[74] DeJulius entered the 2023 American Athletic Conference men's basketball tournament with the nation's longest streak of five or more assists (16 games).