Kadir started boxing at the age of 11 and participated in school boxing championships in the light featherweight class. At 18, he trained under a coach who was an ex-professional boxer. He started competitive boxing in the light flyweight division and started to win matches. In 1968, with a new coach, Kadir won the Singapore Open title which he defended successfully till 1976, when he retired from boxing. In 1969, he won the National Championship and went on to represent Singapore in the
South East Asian Peninsular Games in
Bangkok, which he won a bronze medal. In 1970, Kadir represented Singapore in the Asian Games in Bangkok, in which he lost in the first round. In the
1971 SEAP Games, he won the boxing gold medal in the light flyweight category after defeating defending SEAP champion
Vanla Dawla. For this, the
Singapore National Olympic Council (SNOC) awarded him a merit award. In 1972, Kadir represented Singapore at the
1972 Olympic Games in
Munich but failed to obtain any medal due to an injury, a cut sustained on the eyebrow. In 1973, he won the silver medal at the SEAP Games. In 1974, Kadir won a bronze medal at the
British Commonwealth Games in
New Zealand, in recognition for his contribution to boxing and sports in Singapore. He also attended the
Asian Games in
Tehran but was lost again in the first round. In 1975, Kadir earned another silver at the SEAP Games in Bangkok. In late 1976, Kadir announced his retirement after the President's Cup in
Jakarta. He retired with a record of 11 losses in over 100 fights and reigned as Singapore champion for eight years. ==Coaching career==