Phillips was born in Killeen, Texas and moved to Columbia, South Carolina in the third grade after his parents, who were serving in the U.S. Army, were stationed at Fort Jackson.

[5][6] After LSU head coach Will Wade was fired, Phillips requested and was granted a release from his NLI and reopened his recruitment.

[9] Phillips entered his freshman season at Tennessee as the Volunteers' starting small forward.

[10] He was named to the 2022 Battle 4 Atlantis All-Tournament team after averaging a team-leading 13.3 points per game.

[14] Phillips was selected with the 35th overall pick in the 2023 NBA draft by the Boston Celtics, and was soon traded to the Chicago Bulls via the Washington Wizards.