Choo was given the name "Winston" by his grandfather, who named him after Winston Churchill. He grew up in Makepeace Road in the Newton area and received his education in Monk's Hill School and Anglo-Chinese School. While he was in Anglo-Chinese School, he captained the school's football team, played hockey, and won the Queen's Badge for his activities in The Boys' Brigade.
Military career
Choo enlisted in the Singapore Military Forces in December 1959 and was commissioned as a Second Lieutenant in December 1961 after completing his officer cadet training in Sungai Besi, Malaysia. Following that, he served as a platoon commander in the 1st Battalion Singapore Infantry Regiment and was involved in two major operations. The first was when he was deployed to Sebatik Island, Borneo between 1963 and 1964 during the Konfrontasi. The second was when he led his men in patrolling the streets during the 1964 race riots in Singapore. After Singapore became independent on 9 August 1965, Choo, then the battalion signals officer, was appointed as a military aide-de-camp to Yusof bin Ishak, Singapore's first President. He was recalled to the SAF in 1966 and served as the first Commanding Officer of the 1st Signal Battalion from 1967–1968. Between 1968 and 1969, Choo attended the Long Telecommunications Course at the School of Signals in the United Kingdom, returning to Singapore to serve as the Second-in-Command of the 1st Signal Battalion. In 1970, he was appointed as the Chief of Communications and Electronics. In 1971, Choo served briefly as the CO of the 4th Battalion Singapore Infantry Regiment before attending the Command and Staff College at Fort Canning. In the following year, he attended the US Army Command and General Staff course at Fort Leavenworth in Kansas, United States, and graduated with distinctions in all his subjects. Upon his return to Singapore in September 1972, Choo assumed command of 1 SIR. In the same year, he was named an honorary aide-de-camp to Benjamin Sheares, Singapore's second President, and took up command of the 2nd Singapore Infantry Brigade. He was also promoted to the rank of Colonel. He was later posted to the Defence Ministry 's headquarters, where he was appointed the Head of Training and Head of Organisation and Plans in 1973. In 1974, he succeeded Kirpa Ram Vij as the Director of General Staff. Choo was promoted to Brigadier in 1976 and to Major-General two years later. Between 1978 and 1981, Choo attended a preparatory course in military history at the Department of History of the National University of Singapore. In 1981, he went to the United States to study for a master's degree in military history at Duke University and returned to Singapore in 1982 to resume his post as the Chief of General Staff. Choo was promoted to Lieutenant-General in 1988 and became the first Chief of Defence Force in May 1990 after "Chief of General Staff" was renamed. He retired from the SAF on 30 June 1992, after which he went to Harvard Business School and attended the six-week Advanced Management Program.
Diplomatic career
After retiring from military service, Choo pursued a career in the Ministry of Foreign Affairs. He was Singapore's High Commissioner to Australia and Fiji from 1994–1997 and to South Africa from 2001–2005. He was also a non-resident High Commissioner to Papua New Guinea from 2000–2006 and to Israel since 2005.
Other work
Apart from his military and diplomatic careers, Choo took on non-executive roles in various governmental and non-governmental organisations, including: Deputy chairman, Central Provident Fund ; Chairman, Chartered Industries ; board member, Singapore Technologies ; board member, Keppel-Tat Lee Bank ; Board chairman, Metro Holdings ; Chairman, Singapore Red Cross Society ; Member, Singapore Sports Council ; Member, National Youth Achievement Award Council; Honorary President, Boys' Brigade. Choo has contributed to several publications, including his recollections of Goh Keng Swee and of his time in the Ministry of Foreign Affairs. He also supported the Dads for Life movement in Singapore by contributing to the book Letters from Grandpa and Grandma.
Awards
Throughout his career, Choo won many accolades, some of the medals were displayed at a National Library Board exhibition in 2006. What follows is a partial list of his medals:
