His best mark of 19.49 s (not ratified[5]) makes him the sixth-fastest athlete in history over the distance, only surpassed by Usain Bolt, Yohan Blake, Noah Lyles, Michael Johnson and Letsile Tebogo.

[6] Erriyon Knighton started participating in track and field in 2019 as a freshman at Hillsborough High School in Tampa, Florida.

[10][11] At the US Olympic Trials he would improve that time to 20.04 s in the first round on June 25, and then again to 19.88 s in the semi-finals the following day, breaking Bolt's world U20 record by five hundredths of a second.

[12] On April 30, Knighton set an unratified world junior record in the 200 m at the LSU Invitational in Baton Rouge running a time of 19.49 seconds.

[17] On July 9, 2023, in Eugene during the USA Outdoor T&F Championships, he won his first senior national title by triumphing in the 200 meters with a time of 19.72 seconds.

[21] On March 26, Knighton was provisionally suspended by the US Anti-Doping Agency (USADA) after testing positive for a metabolite of the anabolic steroid trenbolone.

In June the USADA accepted Knighton's explanation that the source of the trenbolone was contaminated meat and ruled that he bore "no fault or negligence" for the positive test.