After going undrafted in the 2016 NFL draft, Robertson-Harris signed with the Chicago Bears on May 9, 2016.[3] On August 30, 2016, he was placed on the reserve/non-football illness list, where he spent his entire rookie season.[4]
In 2017, Robertson-Harris appeared in 13 games, registering 13 tackles, two sacks, and a pass deflection.[5] The following year, he played in every game as he recorded 20 tackles, three sacks and three tackles for loss.[6] He was an exclusive-rights free agent after the 2018 season, but returned to the Bears after being tendered a contract on March 13, 2019,[5] which he officially signed on April 15.[7]
On March 13, 2020, the Bears placed a second-round restricted free agent tender on Robertson-Harris.[10] He signed the tender on April 15.[11] On November 9, it was reported that Robertson-Harris would undergo season ending shoulder surgery after missing out the Bears' Week 9 contest against the Tennessee Titans.[12] He was placed on injured reserve on November 12, 2020.[13]
Jacksonville Jaguars
On March 17, 2021, Robertson-Harris signed a three-year, $23.4 million contract with the Jacksonville Jaguars.[14] On October 2, 2022, Robertson-Harris recorded nine total tackles and a tackle for loss during a 29–21 loss to the Philadelphia Eagles.[15]
On February 25, 2023, Robertson-Harris signed a three-year, $30 million extension with the Jaguars, keeping him under contract through the 2026 season.[16]
Seattle Seahawks
On October 14, 2024, Robertson-Harris was traded to the Seattle Seahawks in exchange for a 2026 sixth-round pick.[17][18]