Howell was drafted by the Ottawa Redblacks with the 55th overall selection, in the seventh round, of the 2018 CFL draft and signed with the team on May 16, 2018.[4] He made the team following training camp and played in his first professional game on June 22, 2018, against the Saskatchewan Roughriders in the 2018 season opening game. He earned his first start at safety on August 11, 2018, against the Montreal Alouettes. Howell played in 13 regular season games and recorded seven defensive tackles and eight special teams tackles while missing five games due to injury. He then played in his first post-season game in the East Final against the Hamilton Tiger-Cats where he recorded a career-high six defensive tackles in a win that sent him to his first Grey Cup game.[5] However, he recorded no stats as the Redblacks lost the 106th Grey Cup to the Calgary Stampeders.[6]
In 2019, Howell played in 14 regular season games and had 14 defensive tackles and eight special teams tackles. He also recorded his first career quarterback sack on September 7, 2019, against the Toronto Argonauts. He signed a one-year contract extension with the Redblacks on January 14, 2020, but with the 2020 CFL season cancelled, it was announced on December 18, 2020, that he had signed another one-year extension with the team.[7][8]
Howell played in 13 games in 2021 and recorded 25 defensive tackles, nine special teams tackles, and two forced fumbles.[9] In 2022, he spent most of the season on the injured list and played in just five games, recording 14 defensive tackles, two special teams tackles, and two forced fumbles.[9] In the 2023 season, he played and started in 13 games, where he had a career-high 39 defensive tackles and one forced fumble.[9]
In 2024, Howell played in 13 games in a backup capacity where he had seven defensive tackles and four special teams tackles.[9] He was again injured for much of the 2025 season and played in six games where he recorded eight defensive tackles.[10] He became a free agent upon the expiry of his contract on February 10, 2026.[11]
