Choo began his playing career playing as a right
full-back with Singapore Chinese Football Association in the
SAFA leagues in 1933.
[9] His performances led to a call-up to the
Singapore FA team in the
Malaya Cup competition. He was converted to a
centre-half as the Lions won the Malaya Cup in 1937 and 1939.
[10] During World War II, he wrote propaganda for the British in Macau.
[11] In 1939, he helped to found the Chinese Athletic Association where he took on the role of player-coach.
[12] He retired as a player to concentrate on his coaching duties in 1949.
From 1951 to 1953, Choo coached the
Indonesia national team on an honorary basis. The team toured Hong Kong in 1953, achieving wins over professional Hong Kong outfits. Choo was appointed
Malaya national coach in 1958.
[13] He led the team to three
Merdeka Tournament titles from 1958 to 1960. With Choo, Malaya also won the
1961 Southeast Asian Peninsular Games football competition and the bronze at the
1962 Asian Games.
[14][15] Choo left Malaysia and returned to Singapore in 1964. He was appointed
Singapore national coach over four stints from 1964 to 1977. He won the Malaysia Cup in 1977, twelve years after Singapore's last triumph.
[16] His achievements earned him the 1977 Coach of the Year award.
[17] The following year, he was honoured with the
Pingat Bakti Masyarakat medal for his services to Singapore football.
[18]
Choo had a skin infection of his leg which he left untreated during the 1977 season. With diabetes as a complication, his condition worsened and he was forced to amputate his gangrenous right leg in September 1977.
[19] He returned to coaching during a brief stint with
Johor FA in 1980 but left in early 1981.
[20] In June 1983, he was admitted to hospital with kidney problems.
[21] He died at the age of 68 on 30 June.
[7]