Mailula made his senior debut for
Mamelodi Sundowns in the
South African Premier Division during a 1–0 win against
Chippa United in September 2022. He scored his first senior goals on 14 October 2022, in a match against
La Passe FC in the
CAF Champions League, netting a hat-trick. He scored his first league goals on 25 October, netting a brace against
Maritzburg United. Mailula was subsequently named the league's Young Player of the Season for his debut campaign. In July 2023, Mailula signed with
Major League Soccer club
Toronto FC, signing through the 2026 season, with an option for 2027. He made his debut on 26 August 2023, in a substitute appearance, against the
Columbus Crew. He scored his first goal for the club on 24 April 2024 in a
2024 Canadian Championship match against semi-pro club
Simcoe County Rovers FC. In 2024, he spent some time on loan with the second team,
Toronto FC II, in
MLS Next Pro. In August 2024, he went on loan with Moroccan
Botola club
Wydad AC through 31 July 2025, with an option for a permanent transfer at the conclusion of the loan, reuniting him with
Rhulani Mokwena, who was his coach at Mamelodi Sundowns. He scored his first goal for Wydad on 3 November 2024, netting a late winner in a 1–0 victory over
FUS Rabat. In September 2025, he was loaned to Belgian
Challenger Pro League club
Kortrijk through June 2026, with Kortrijk holding a purchase option. ==International career==