Cumming finished fourth at the 2015 African Junior Championships in Ethiopia, narrowly missing out on the podium.

[2] That same year he began competing at the collegiate level for North-West University, breaking the Varsity Sports record with a personal best throw of 58.13 m at his maiden meet in Stellenbosch.

[3] He was selected for his first senior international competition, the 2018 African Championships held in Nigeria,[4] though he finished in sixth place after throwing for 67.37 m.[5] In 2019, Cumming won a bronze medal at the South African Championships before placing eighth at the Summer Universiade in Italy.

[6][7] Cumming won his first senior national title at the 2021 South African Championships, recording a throw of 72.78 m to defeat incumbent champion Tshepang Makhethe.

[9][10] Then, in June, he captured the continental title at the African Championships in Mauritius with a throw of 69.13 m in the final round, finishing just ahead of Tshepang Makhethe for the gold medal.