He led the school to a 29–2 record that year, and they won the California Interscholastic Federation (CIF) Division II state championship.

However, when UNLV's men's basketball program was placed on probation due to recruiting improprieties, O'Bannon rescinded his commitment and instead attended UCLA.

[5] Six days before the official start of practice at UCLA, O'Bannon tore his anterior cruciate ligament as he landed awkwardly on a dunk during a pickup game with other Bruins.

[12] In his two professional seasons, he was unable to find a place in the NBA, being too lean to play down low and not quick enough with his rebuilt knees to guard the perimeter.

"[5] After his NBA career, O'Bannon played professional basketball seven years overseas in Italy, Spain, Greece, Argentina and Poland (in Anwil Włocławek, Polonia Warsaw and Astoria Bydgoszcz).

[15] In 2006, while employed as a salesman at the dealership, O'Bannon told the Los Angeles Times, "People see me and remember me and I'm proud to tell them—'No, I don't play.

[17] O'Bannon was the lead plaintiff in O'Bannon v. NCAA, an antitrust class action lawsuit filed against the National Collegiate Athletic Association (NCAA) on behalf of its Division I football and men's basketball players over the organization's use for commercial purposes of the images of its former student athletes.

The suit argued that upon graduation, a former student athlete should become entitled to financial compensation for future commercial uses of his or her image by the NCAA.

[18][19] In January 2011, Oscar Robertson, considered one of the greatest basketball players of all time, joined O'Bannon in the class action suit.

[20] On August 8, 2014, Judge Claudia Wilken ruled that the NCAA's long-held practice of barring payments to athletes violated anti-trust laws.

[21] In March 2015, O'Bannon appeared in a faux commercial on Last Week Tonight with John Oliver on HBO that criticized the NCAA's payment practices regarding student athletes.

[2] O'Bannon supported the Fair Pay to Play Act, a California law that allows college athletes to receive endorsement deals.