The Angels selected Jewell in the fifth round of the 2014 MLB draft. He signed and spent 2015 with both the Arizona League Angels and the Orem Owlz, posting a 1–2 record and 3.59 ERA in 12 games over 42.2 innings between the two teams. In 2015, he played for the Burlington Bees in the Class AMidwest League where he compiled a 6–8 record and 4.77 ERA in innings pitched. Baseball America named him the Angels #5 prospect entering 2016 season. In 2016, he played for the Inland Empire 66ers of the Class A-Advanced California League, pitching to a 2–15 record, 6.31 ERA, and 1.87 WHIP in 28 games over 137 innings. Jewell began 2017 back with the 66ers, and after posting a 2.25 ERA in his first three starts, was promoted to the Mobile BayBears of the Class AASouthern League, where he finished the season, going 7–8 with a 4.84 ERA in 24 games. After the 2017 season, the Angels added Jewell to their 40-man roster. He began the 2018 season with the BayBears, and after seven games was promoted to the Salt Lake Bees of the Class AAAPacific Coast League, with whom he was 2-4 with a 3.60 ERA in 25 innings. The Angels promoted Jewell to the major leagues on June 15. He made his major league debut the next day against the Oakland Athletics at Oakland Coliseum, pitching a scoreless eighth inning in which he earned his first major league strikeout against Franklin Barreto. During Jewell's third MLB game, on June 27 against the Boston Red Sox, he left the game after an apparent ankle injury suffered while trying to make a play at the plate. The following day, the Angels placed Jewell on the disabled list due to a right fibula fracture, requiring season-ending surgery. For the season with the Angels, he pitched 2 innings and was 0-1. In 2019 with Salt Lake he was 4-4 with 8 saves and a 5.26 ERA in 37.2 innings, and with the Angels he was 0-0 with a 6.84 ERA in 26.1 innings. Jewell was designated for assignment on January 6, 2020, following the acquisition of Kyle Keller.
He was claimed off waivers by the San Francisco Giants on January 13. Jewell was designated for assignment by the Giants on January 21, and outrighted on January 24.