On November 11, 2018, Kirkwood made his professional regular season debut and caught two passes for 45 yards and made one tackle on special teams during a 51–14 victory at the Cincinnati Bengals in Week 10.[12]
On September 17, 2019, Kirkwood was placed on injured reserve with a hamstring injury.[13] He was designated for return from injured reserve on November 13, 2019, and began practicing with the team again.[14] However, he was not activated by the end of the three-week practice window on December 4, 2019, and remained on injured reserve for the rest of the season.[15]
Carolina Panthers
On April 1, 2020, Kirkwood signed with the Carolina Panthers reuniting him with former Temple head coach Matt Rhule and former college teammates Robby Anderson, P. J. Walker, and Colin Thompson.[16] Kirkwood was placed on injured reserve on September 7, due to a shoulder injury.[17] He was designated for return from injured reserve on September 30, 2020, and began practicing with the team again.[18] He was activated on October 17, but re-injured his left clavicle in the next game and was placed back on injured reserve on October 20.[19][20]
On February 22, 2021, Kirkwood signed a one-year contract extension with the Panthers.[21] He was waived on August 31, 2021, and re-signed to the practice squad the next day.[22][23] Ahead of the Week 8 game against the Atlanta Falcons, Kirkwood was promoted to the active roster.[24]
On June 6, 2022, Kirkwood re-signed with the Panthers.[25] He was released on August 30, 2022.[26]
New Orleans Saints (second stint)
On September 28, 2022, Kirkwood was signed to the Saints' practice squad.[27] On October 15, 2022, Kirkwood was promoted to the active roster.[28] He was released on October 29 and re-signed to the practice squad. He was promoted on January 4, 2023.
Kirkwood re-signed with the Saints on February 17, 2023.[29]
Baltimore Ravens
On June 28, 2024, Kirkwood signed with the Baltimore Ravens.[30] He was released on August 27, and re-signed to the practice squad.[31][32]