Aminu was selected by the Los Angeles Clippers in the 2010 NBA draft with the eighth overall pick, and has also played for the New Orleans Pelicans, Dallas Mavericks, Portland Trail Blazers, and Orlando Magic.

Aminu went to Norcross High School and was ranked as one of the top college recruits in the nation from the class of 2008.

[2] In his junior year, Aminu and teammate Gani Lawal led Norcross to a 30–3 record and a #12 national seed.

Aminu was a member of the 2008 McDonald's All-American Team and played in the Jordan Brand Classic where he had 12 points and 13 rebounds.

[6] In the final game of the 2012–13 regular season on April 17, Aminu recorded 16 points and a career-high 20 rebounds in an 87–99 loss to the Dallas Mavericks.

He made his debut for the Trail Blazers in the team's season opener against the New Orleans Pelicans on October 28, recording 9 points and 8 rebounds in a 112–94 win.

[15] He set a new career high five days later, scoring 28 points while hitting a career-high six three-pointers in a 116–109 win over the Boston Celtics.

[16] On April 6, he scored 27 points in a 120–115 win over the Oklahoma City Thunder, helping the Trail Blazers clinch a postseason berth.

In the first round of the playoffs, the Trail Blazers faced the fourth-seeded Los Angeles Clippers, and in a Game 4 win on April 25, Aminu recorded a career-high 30 points and 10 rebounds, helping the team tie the series at 2–2.

After starting in the Trail Blazers' first eight games of the 2016–17 season, Aminu was ruled out for a number of weeks with a calf injury on November 11, 2016.

[28] On March 25, 2021, Aminu and Nikola Vučević were traded to the Chicago Bulls in exchange for Wendell Carter Jr., Otto Porter Jr. and two future first-round picks.

[29] On August 11, 2021, Aminu, Thaddeus Young, and several draft picks were traded to the San Antonio Spurs in exchange for DeMar DeRozan.

On August 30, 2015, Aminu with the D'Tigers of Nigeria won the 2015 FIBA Africa Championship (AfroBasket) in Tunisia by defeating Angola 74–65.