Bey was born Apr. 9, 1999 in Charlotte, North Carolina but grew up in Largo, Maryland. He is the son of Drewana Bey, a high school principal who played college basketball at Charlotte. As a freshman, Bey attended DeMatha Catholic High School before transferring to Sidwell Friends School, known for its strength in academics and basketball. Bey also played AAU ball with D.C. Premier. He helped lead Sidwell Friends to a state championship as a junior, averaging 14.5 points, 6.5 rebounds, 2.0 assists and 2.0 steals per game. As a senior, he averaged 21 points and eight rebounds per high school contest. For college, Bey originally committed to NC State, then de-committed and opted to attend Villanova one month later. As a sophomore at Villanova, Bey won the Julius Erving Small Forward of the Year award and was named to the First-team All-Big East.