[12] On July 16, 2017, Darby was signed to the practice roster of the Toronto Argonauts of the Canadian Football League.

[13] He played in eight regular season games with the Argonauts in 2017 where he had 18 defensive tackles and one interception that he returned 75 yards for his first career touchdown.

[14] On July 19, 2021, Darby was traded to the Winnipeg Blue Bombers in exchange for offensive lineman Terry Poole.

[15] He played in 11 regular season games where he had 34 defensive tackles and was named a CFL West All-Star.

[16] Darby signed with the Hamilton Tiger-Cats as a free agent on February 10, 2022, after initially verbally agreeing to join the Ottawa Redblacks.

[19] He also played in the West Final playoff and the 109th Grey Cup game, where he recorded three defensive tackles, but the Blue Bombers lost to the Toronto Argonauts.