He was signed by the Chargers as an undrafted free agent in 2020 following his college football career with the Liberty Flames.

Lemonier signed with the Los Angeles Chargers as an undrafted free agent following the 2020 NFL draft on April 26, 2020.

[1] He was waived during final roster cuts on September 5, 2020,[2] and signed to the team's practice squad the next day.

[12] On September 2, 2021, Lemonier was signed to the Detroit Lions practice squad,[13] promoted to the active roster on October 6,[14] and waived on May 16, 2022.

[17] Lemonier was selected by the Arlington Renegades in the 2023 XFL Draft,[18] but instead signed with the Houston Gamblers of the USFL on December 31, 2022.