Kay was born in Auckland in 1926, his father owned and operated a womenswear manufacturing and retailing business, and his mother was a homemaker. The family lived in Remuera, and Kay attended King's College, Auckland from 1939 to 1943, where he was a house prefect, and won a tennis championship and an intercollegiate high jump competition. His mother supported his sports, attending all his sports meetings, and telling him to dig a pit in part of the family tennis court so he could practice his jumping. Kay later enrolled in accounting at the University of Auckland, while not completing his studies he was active in athletics and played rugby. He worked at and later purchased his father's business. Kay was Jewish. Kay competed in the 1950 British Empire Games in Auckland, coming 8th in the hop step and jump at 13.91m. He was the New Zealand triple jump champion in 1950 with a jump of 14.14m, and in 1951 with a jump of 14.31m. The University of Auckland Athletics Club successfully nominated Kay to lead the national team to the 1962 Commonwealth Games team in Perth, where New Zealand won 32 medals including 10 golds. He achieved a goal to raise $150,000 for the 1974 Commonwealth Games in Christchurch, and was on the board of directors for the 1990 Commonwealth Games in Auckland. Kay founded the Auckland Joggers Club with Arthur Lydiard in 1962, and the annual Auckland Round the Bays fun run in 1973. With Douglas Myers in 1977 he jointly founded the New Zealand Sports Foundation, where he served as Governor for 16 years. He was a founder and the chairman of the Peter SnellInstitute of Sport in 2000, and organisation with the objective of finding and promoting sporting talent in New Zealand. He was first elected to the Auckland City Council in 1971, and was later elected mayor of Auckland in 1980, succeeding Dove-Myer Robinson. He was appointed a Commander of the Order of the British Empire in the 1990 New Year Honours, for services to sport, politics and the community. He died in 2008, more than one year after suffering a major stroke, and was survived by his wife and three sons. The main stand of Mt Smart Stadium was named the Colin Kay stand in his honour.
