He represented India in the 400m competition of the 1956 Melbourne Olympic Games. His inexperience meant that he did not progress from the heat stages but a meeting with the eventual champion, Charles Jenkins, both inspired him to greater things and provided him with information about training methods.
In 1958, Singh set records for the 200m and 400m in the National Games of India, held at Cuttack,and also won gold medals in the same events at the Asian Games. He then won a gold medal in the 400m competition at the 1958 British Empire and Commonwealth Games with a time of 46.6 seconds.This latter achievement made him the first gold medalist at the Commonwealth Games from independent India.As of 2013, he is still the only male Indian to have won an individual athletics gold medal at those Games.
In 1960, Singh was persuaded by Jawaharlal Nehru to set aside his memories of the Partition era to race successfully against Abdul Khaliq in Pakistan, where a comment by the then General Ayub Khan led to him acquiring the nickname of The Flying Sikh.In the same year, at the Olympics in Rome, he was involved in a close-run final race in the 400m competition, where he was placed fourth.He had set a world record of 45.8 seconds in France, had beaten all the leading contenders other than Otis Davis, and a medal had been anticipated because of his good form. However, he made mistakes when leading the race, slowing down in the belief that his pace could not be sustained and looking round at his fellow competitors. Singh, who ran the race barefooted, believes that these errors caused him to lose his medal opportunity. Davis, Carl Kaufmann and Malcolm Spence all passed him, and a photo-finish resulted. Davis and Kaufman were both timed at a world-record breaking 44.9 seconds, while Spence and Singh broke the Olympic record with times of 45.5 and 45.6 seconds, respectively.[b] The Age noted in 2006 that “Milkha Singh is the only Indian to have broken an Olympic track record. Unfortunately he was the fourth man to do so in the same race.
In the 1962 Asian Games, held in Jakarta, Singh won gold in the 400m and in the 4 x 400m relay.He also competed in the 4 x 400m relay at the 1964 Olympic Games, held in Tokyo, where the team finished fourth in the heat stages.