Peirson was eligible for the
2018 CFL draft, but was not selected. Instead, he signed as an
undrafted free agent with the
BC Lions on May 9, 2018. Following an impressive training camp, he was signed to the team's practice roster to begin the
2018 season. He played and started in the last five games of the regular season in 2018. He did not play in 2020 due to the cancellation of the
2020 CFL season. Following the Lions' training camp in
2021, Peirson made the team's active roster as a backup offensive lineman. He dressed in all 14 regular season games as a backup in the
pandemic-shortened 2021 season. On February 2, 2026, Peirson re-signed with the Lions, on a one-year contract extension. ==Personal life==