[3] In the 2019 Las Vegas Bowl, Sirmon recovered a fumble as the Huskies beat Boise State.
[7] In week nine of the 2021 season, Sirmon recorded his first career interception, picking a pass in the redzone by quarterback Tanner McKee, helping Washington beat Stanford 20–13.
[12][13] Sirmon started the 2022 season strong, as in week three he totaled 15 tackles with two going for a loss, and 1.5 sacks, but the Golden Bears fell to Notre Dame 24–17.
[14] In week seven, Sirmon picked off a pass by Owen McCown, but California lost 20–13 against Colorado.
[15] In week twelve, Sirmon recovered a fumble that he returned for a touchdown that would win the Golden Bears the game, as they would beat Stanford 27–20.