[2] Diogu attended Arizona State University, where he excelled on the team under head coach Rob Evans.

[4] On January 17, 2007, Diogu, whom Larry Bird called the "gem" of the deal, was traded to the Indiana Pacers along with teammates Mike Dunleavy Jr., Troy Murphy, and Keith McLeod for Stephen Jackson, Al Harrington, Šarūnas Jasikevičius, and Josh Powell.

Diogu was traded to the Sacramento Kings for the Chicago Bulls' Michael Ruffin on February 18, 2009.

In the fall of 2012, Diogu signed with the Guangdong Southern Tigers of the Chinese Basketball Association.

[11] After the season in China, he joined the Leones de Ponce in Puerto Rico.

[16] On April 29, 2014, Diogu re-joined the Leones de Ponce of the Baloncesto Superior Nacional.

[19] In November 2016, Diogu signed with the Jiangsu Monkey King for the purpose of replacing DeJuan Blair.

[20] In January 2018, Diogu signed with the Sichuan Blue Whales for the purpose of replacing Jamaal Franklin.

[25] On February 12, Diogu made his debut scoring 8 points and 4 rebounds against Burgos in the semifinal of the 2022 FIBA Intercontinental Cup.

[26] Diogu has played with the senior men's Nigeria national basketball team.