Baltimore Ravens
2017 season
The Baltimore Ravens selected Bowser in the second round with the 47th overall pick in the 2017 NFL draft.[23] He was the third outside linebacker to be selected.[24] On May 5, 2017, the Ravens signed Bowser to a four-year, $5.57 million contract with $3.37 million guaranteed and a signing bonus of $2.19 million.[25]
Bowser made his NFL debut in the 2017 season opener against the Cincinnati Bengals. He recorded one tackle in the 20–0 victory over the Bengals.[26] He recorded his first NFL interception in Week 2 against quarterback Kevin Hogan of the Cleveland Browns, returning it for 27 yards and setting up a critical touchdown by the Ravens' offense before halftime.[27] Overall, in his rookie season, he finished with three sacks, nine tackles, one interception, and three passes defensed.[28]
2018 season
Bowser finished the 2018 season with .5 sacks and 11 total tackles in 15 games.[29]
2019 season
In Week 10 of the 2019 season, Bowser recorded a 33-yard fumble return for a touchdown in the 49–13 victory over the Bengals.[30] He followed that up with a two-sack performance in a 41–7 victory over the Houston Texans in the next game.[31] He finished the 2019 season with five sacks, 24 total tackles, two passes defended, and one forced fumble.[32]
2020 season
Bowser was placed on the reserve/COVID-19 list by the team on November 3, 2020,[33] and activated four days later.[34] In the 2020 season, Bowser finished with two sacks, 34 total tackles, three interceptions, and five passes defended.[35]
2021 season
On March 16, 2021, Bowser re-signed with the Ravens, on a four-year, $22 million deal, with the potential to rise to $27 million.[36] In the final seconds in the fourth quarter Bowser sacked Andy Dalton for a loss of 18 yards, which yielded a 16–13 win over the Chicago Bears on November 21, 2021.[37] The following week, against the Browns, Bowser recorded a sack on Baker Mayfield, as well as a game sealing tackle on fourth down in the 16–10 victory.[38] Bowser finished the 2021 season with seven sacks, 59 total tackles, four passes defended, and two forced fumbles.[39]
On January 14, 2022, Bowser underwent surgery to repair a torn Achilles.[40]
2022 season
On August 26, 2022, Bowser was placed on the reserve/PUP list to start the season.[41] He was activated on November 1.[42] He appeared in nine games in the 2022 season. He finished with two sacks, 13 total tackles, two passes defended, and one forced fumble.[43]
2023 season
Bowser was placed on the reserve/non-football injury list to start the season due to a knee injury over the summer that had setback before the season.[44][45]
On March 13, 2024, Bowser was released by the Ravens.[46]