Born in Sebokeng,[1] Mahlasela played youth football at Orlando Pirates, but failed to make a first team appearance there.
[2] He joined Roses United in 2012 before going on to play for Sivutsa Stars on loan and later Royal Eagles.
[5] He made his debut for Celtic, and only appearance for the club over the course of the 2015–16 season on 18 December 2015, coming on as a late substitute in a 2–1 defeat away to Chippa United.
[10][11] Following his return from injury, he made his debut for Kaizer Chiefs on 7 August 2018 as a late substitute in a home defeat to Bidvest Wits.
[13] He appeared for the first time for Polokwane City on 11 January 2020, coming on as a first-half substitute in a 1–0 defeat away at Baroka.