[1] On March 3, 2018, Porter recorded 22 points and 11 rebounds in a Class 3A state championship game loss to Garfield High School.

[17] At the conclusion of his freshman season, Porter announced his intention to forgo his remaining collegiate eligibility and declare for the 2019 NBA draft.

[20] On October 23, Porter made his debut in the NBA, playing in an 85–94 loss to the Orlando Magic and finishing with one rebound, two assists, and a steal.

[29] Porter made his official debut with the Rockets on March 11, 2021, contributing 13 points, ten assists and five rebounds in a game lost against the Sacramento Kings.

On January 1, 2022, during a 111–124 loss to the Denver Nuggets, Porter and teammate Christian Wood got into a verbal altercation with Rockets assistant coach John Lucas at halftime.

Porter then threw an object into the locker room and left the Toyota Center, the arena where the Rockets were playing, before the game ended.

Porter Jr. posted a triple-double against Panathinaikos with a stat line of 23 points, 14 rebounds and 10 assists, the first in Greek Basket League playoff history.

On offense, he possesses a strong isolation game that is complemented by a high level of athleticism that allows him to be an effective scorer on the perimeter, at and above the rim, and in transition.

[41] His elite handling skills allow him to create space and defer to either a step-back jumper, a pull-up shot out of a crossover, or a behind-the-back dribble pull-back.

[17][48] Analysts identified his shot selection, assist-to-turnover ratio, and foul-shooting as a point of improvement in his game in addition to other miscellaneous off-the-court concerns.

[42] On November 15, 2020, Porter Jr. was charged by Mahoning County police following a single car accident for improper handling of a firearm in a vehicle.

[51] On September 11, 2023, Porter Jr. was arrested and charged by the New York Police Department for allegedly assaulting his girlfriend, Kysre Gondrezick.

[53] On January 23, 2024, he accepted a plea deal with the NYPD, pleading guilty to a misdemeanor charge of reckless assault and a second-degree harassment violation.