Cumming won the silver medal behind Nikolai Panin at the London Olympics in 1908 , the first to feature figure skating, in the competition for special figures that were unique to these Olympics. At 19, he was the youngest participant in figure skating at these Olympic Games.
In 1912 and 1914, Cumming was the British individual race champion. At the World Championships in 1912 he finished fifth in the individual run and also took part in pair skating alongside a Mrs. Cadogan, with whom he finished seventh. In 1913 he only started pair skating with Mrs. Cadogan and finished seventh again.
In May 1914, Cumming had a motorcycle accident as a result of which he fell ill with tetanus and died a little later.