Whilst at school Deng Chueng-Hwai learned carpentry and also developed into a decent cyclist, becoming a multiple-time champion. Deng found a job at a woodwork shop, cycling around 30 kilometres each day to get to and from work. In 1957 he took part in first competitive race, finishing second in the local May Day Labour Games. After winning a provincial championship two years later, Deng then dominated in events from 4,000 metres to 200 kilometres over the next eight years. He was soon selected to represent the Taiwanese national team, riding in events in Hong Kong, Seoul, and Manila, in addition to earning a place on the Olympic team. In 1964 he competed in both the individual road race and the 100 kilometres team trial at the Tokyo Games, finishing 25th in the latter. Four years later he once again rode in the same two events at the 1968 Mexico City Olympics. After the Mexico City Games he eventually gave up on cycling, taking an office job in Taipei.