[2] He averaged 12.5 points and 7.9 rebounds per game for the Trailblazers as a junior, leading the team to the CIF Southern Section Open Division final before losing to state champion Chino Hills High School.

[3] In the summer of 2016, he averaged 13.7 points and 7.3 rebounds per game in the Nike Elite Youth Basketball League, playing alongside Marvin Bagley III.

In October 2016, Riley committed to playing college basketball for UCLA over offers from Kansas, USC, UConn and Oklahoma.

[4] Prior to the start of his freshman season, Riley was one of three UCLA players (along with Jalen Hill and LiAngelo Ball) who were arrested in China for allegedly shoplifting before their game against Georgia Tech.

[12] He averaged 10 points and 5.4 rebounds per game as a junior, shooting 53.8% from the field and helping the Bruins reach the Final Four.

[13] In the 2021–22 season opener against Cal State Bakersfield, he sustained a left medial collateral ligament sprain after a collison in the first half.

[17] After going undrafted in the 2022 NBA draft, Riley signed with KK Rogaška of the Premier A Slovenian Basketball League.