He played for the Norfolk State Spartans, and led them to a victory over the #2 seed Missouri Tigers in the second round of the 2012 NCAA Men's Division I Basketball Tournament.

[1] His parents are Tommie (who moved to New York from Mississippi in 1963, worked for the Metropolitan Transportation Authority, and died in a car accident in September 2015) and Regina O’Quinn.

In his senior year, he averaged 20 points, 12 rebounds, and 3 blocks per game, but his only scholarship offer was to Norfolk State University.

[9] He was a first-team All-Queens and third-team All-Public School Athletic League (PSAL) selection in his senior year.

[10] O'Quinn originally planned on pursuing a career in football even after receiving a scholarship from Norfolk State mainly because of his basketball ability.

O'Quinn could have given up basketball the way he had with football, but this time chose the other choice and focused on pursuing a career in the NBA.

[4] O'Quinn led the MEAC in blocks and rebounds, was second in field goal percentage (.556), and finished fifth in points per game.

[4] Norfolk State made the NCAA Division I men's basketball tournament as a 15 seed, the Spartans (making their first-ever postseason appearance) upset the second-seeded Missouri Tigers in the Round of 64.

[19] After spraining his ankle in the season opener against the New Orleans Pelicans on October 28, 2014, O'Quinn missed 15 consecutive games before returning to action on November 16.

[28] On November 25, 2017, O'Quinn had his first double-double of the season with 20 points and 15 rebounds starting in place of the injured Enes Kanter in a 117–102 loss to the Houston Rockets.

[29] On July 9, 2018, O'Quinn signed a one-year deal with the Indiana Pacers,[30] after opting out of the final year of his contract in New York.

[32] On January 20, 2021, O'Quinn signed a one-year deal with Fenerbahçe of the Turkish Basketball Super League and the EuroLeague.