A dashing all rounder, Constantine at his peak was a mercurial bowler of genuine pace, an athletic fielder, and a flashing stroke player capable of tearing any attack to shreds on his day. In the days before West Indians were seen in county cricket, Constantine became a legend in the highly competitive Lancashire Leagues where his deeds, and demeanour, are remembered to this day. He was a Wisden Cricketer of the Year in 1940.
After retiring from cricket, he became a commentator for the BBC. During World War II, Constantine worked as a welfare officer for the Ministry of Labour. Based in Liverpool, his main responsibility was to help West Indian immigrants find employment in Britain.
In 1943 he was taking a vacation and was the cricket captain for the West Indies. He and his family had a reservation to stay at the Imperial Hotel in Russell Square, London. He was reassured that he and his family were welcomed and would be treated with the utmost respect. This was not the case; when they arrived at the Imperial Hotel his family were not welcomed. They were treated as outcasts and Constantine was outraged. Constantine brought a civil action against the hotel for breach of contract and racial discrimination.
The judge who heard the case was sympathetic to Constantine and his family. He accepted the case and accepted the evidence brought by Constantine and his legal team. He rejected the evidence of the Imperial Hotel that they showed no discrimination based on Constantine’s skin colour. Constantine was awarded £5 in damages. However, the ruling did not end the colour bar in British hotels and other public establishments. Constantine later wrote Colour Bar (1954), with his friend, C. L. R. James. The book dealt with racial prejudice in Britain. In 1945 he was awarded an MBE.
After studying law, Constantine gained entrance to the English bar in 1954. Later he returned to Trinidad and Tobago where he became involved in politics. A member of the People's National Movement, he was elected to the Legislative Council after winning the Tunapuna seat in the 1956 elections. He served in the government as Minister of Community Works and Utilities. When the country gained independence in 1962, he became his country's first High Commissioner in London. Knighted in the same year, he became an honorary Master of the Bench in 1963.
In 1964 he resigned but stayed in Britain where he held several important positions. This included being a Governor of the BBC and a member of the Race Relations Board and the Sports Council. He eventually settled in Lancashire with his family. In 1967 he was elected Rector of the University of St Andrews, and in 1969 he became the first person of African descent to be given a life peerage, being created Baron Constantine, of Maraval in Trinidad and Tobago and of Nelson in the County Palatine of Lancaster. Constantine died of lung cancer in Hampstead, London, on 1 July 1971.