Xavier Tillman Sr. was born January 12, 1999 in Grand Rapids, Michigan. He is the son of Tanya Powell-May and Roosevelt Tillman. Tanya played college basketball at the University of Michigan, earned All-Big Ten Second Team honors and left as the program's all-timer leader in rebounds. Xavier has three older brothers and a younger sister. Tillman was 6-foot-5 when he was 14 years old and attended Forest Hills Central High School in Grand Rapids. After two years at Forest Hills, Tillman transferred to Grand Rapids Christian. At the close of his senior year, Tillman was a finalist for the Mr. Basketball of Michigan award and was named an Associate Press Class A First Team All-State member. The 6-foot-8 forward played three years of basketball at Michigan State (2017-2020) before declaring for the 2020 NBA Draft. Tillman studied journalism at Michigan State. Fans can follow the former Spartan on Twitter @Rookiedunker.