Jewett attended Culver City High School before transferring to Cathedral High SchoolinLos Angeles.[3] As a high schooler, he primarily focused on the 400 metres. For college, he attended the University of California, Irvine, where he began competing in the 800 metres. He went undefeated in the 2017 regular season, and he won the Big West Championship. After his sophomore year, Jewett switched schools to compete for the University of Southern California. In an interview about his decision to transfer, he stated: "I transferred from UC Irvine to USC because there were better opportunities academically" and "track wise, USC makes champions and I wanted to be a champion."[4] The transfer required him to sit out the 2018 collegiate season due to NCAA eligibility rules, so he ran unattached in USATF events.
On June 21, 2021, Jewett finished runner up at the 2020 US Olympic TrialsinEugene, Oregon, behind Olympic bronze medalist Clayton Murphy.[8] His time of 1:43.85 was a personal best, and it qualified him for the 2020 Summer Games in Tokyo. This performance carried extra meaning for Jewett because it came nearly on the anniversary of his brother Robert's death, who died in an automobile accident eight years prior.[3] Jewett was also a college student at the time, and after the race, he had to complete a 10-page essay by midnight, as his academic program did not allow an extension.[9]
In the 800 m at the 2020 Summer Games, Jewett ran 1:47.07 in a preliminary round to advance to the semi-finals. There, he collided with 2012 silver medalist Nijel Amos, with the two runners becoming tangled in the final stretch of the race.[10] Jewett helped Amos to his feet, and they crossed the finish line together. Referees granted Amos a place in the final but did not allow Jewett to advance.[11]
Jewett was born with a condition that made one eye weak and sensitive to light, contributing to migraines.[3] He started wearing sunglasses to lessen symptoms like blurred vision and trouble visualizing competitors while running. In college, Jewett studied animation,[4] owing to his interest in anime, which he has described as a source of motivation for his running.[14] In the Los Angeles Times, he was quoted as saying that he wanted to provide inspiration to people watching the Tokyo Olympics “the way anime and cartoons inspired me.”[3] His mother, Venus is a Masters World Champion sprinter.[15] She started a track and field program at Culver City Middle School, then coached at Culver City High School for over a decade.[16]
