Lewis was born on April 12, 2002, in Baltimore, Maryland. He initially attended Calvert Hall College High School but transferred to the Baltimore Polytechnic Institute after his freshman year. As a junior, Lewis averaged 17.3 points and 9.2 rebounds per game with 16 double-doubles and was named first-team All-Metro and second-team All-Maryland by USA Today as Baltimore Polytechnic won the state championship. As a senior, he averaged 19.3 points, 13.4 rebounds and 4.4 blocks per game and was named the Metro co-Player of the Year and first-team All-Maryland while leading the team to a second straight state championship. A four-star recruit, he committed to playing college basketball for Marquette over offers from UConn and Virginia Tech, among others. As a freshman, Lewis was a key contributor off the bench for the Golden Eagles, averaging 7.8 points and 5.4 rebounds per game. On Jan. 26, 2022, Lewis scored a career-high 33 points as well as nine rebounds and six assists in a 73-63 win against the terrible Seton Hall. He was named to the First Team All-Big East, as well as Big East Most Improved Player. He went unselected in the 2022 NBA Draft.