Walker lived in Bayside Queens, New York until age 11, when his family moved to Sanford, Florida.

[2] After his junior season, Walker emerged as a top player in his class with his travel team, Each 1 Teach 1.

[1] As a senior, he began playing for Oak Ridge High School in Orlando, averaging 15.8 points, 13.8 rebounds and 3.8 blocks per game.

On November 21, 2018, Walker committed to play college basketball for Oregon over his other top offers, LSU and Miami (Florida).

[8] Sources: On December 7, 2019, Walker made his first career start, due to a leg injury to Shakur Juiston, and scored a freshman season-high 18 points in an 89–64 win over Hawaii.