Anunoby was born in London to Nigerian parents. His father Ogugua Sr., who was born in Nigeria, was teaching in England at the time. Anunoby's mother died of cancer soon after he was born. When he was four years old, Anunoby's family moved to the United States to Jefferson City, Missouri, where his late father was a professor at Lincoln University. Anunoby played for Jefferson City High School. During his senior season, he averaged 19.1 points and 8.6 rebounds per game and was named a finalist for Mr. Basketball in the state of Missouri. In October 2014, Anunoby chose to attend Indiana University over Georgia, Iowa, George Mason, and Ole Miss.
College career
Freshman year
As a freshman in 2015–16 at Indiana, Anunoby appeared in 34 games, averaging 4.9 points, 2.6 rebounds and 0.5 assists per game.
Sophomore year
Anunoby was selected as a Pre-season All-American by The Sporting News. On 18 January 2017, Anunoby injured his right knee against Penn State, causing him to undergo season-ending knee surgery. On 10 April 2017, Anunoby declared his intention to enter the 2017 NBA Draft and hire an agent, ending his tenure with the Hoosiers.
Professional career
Toronto Raptors (2017–present)
On 22 June 2017, Anunoby was selected with the 23rd overall pick in the 2017 NBA draft by the Toronto Raptors. On 9 July, he signed a rookie-scale contract with the Raptors. On 14 November, Anunoby made his first career start, against the Houston Rockets. He finished the game with 16 points, 2 rebounds, 1 assist and 1 steal in 30 minutes. By December 15 he led starter rookies in offensive and defensive rating, besides having the third most True Scoring % and best Turnover-to-Assist ratio for a non-guard. On 3 April 2018, he hit his first ever buzzer beater, against the Cleveland Cavaliers. On 29 January 2019, Anunoby was named a member of the World Team for the 2019 Rising Stars Challenge. In April 2019, Anunoby had an emergency appendectomy, which caused him to miss most of the Raptors' championship playoff run. He dressed for the NBA Finals but did not play. On March 1, 2020, Anunoby recorded a career-high 32 points and seven steals, along with seven rebounds and three assists in a 133–118 loss against the Denver Nuggets.