Ait-Slimane began playing football as a 5-year-old with FC Ecublenbs Vaud in Switzerland, before returning to Canada with AS Saint-Lambert for 3 years.
[1] He joined the Montreal Impact's academy team in the Canadian Soccer League's first division in 2012.
[4] Ait-Slimane would contribute a goal in the semifinal round against the York Region Shooters and helped advance Montreal to the championship final.
[10] His final run with the academy was during the 2014 season when the team competed in the American-based USL Premier Development League.
[12][13][14] He made his professional debut for the club on March 28 in a 2–0 defeat to Toronto FC II.