Robert Le Sueur was born in Jersey. He had recently left school when the Second World War broke out in 1939. At the fall of France in 1940 his family chose to remain in Jersey. Le Sueur was working as a clerk in an insurance company at the time, and he remained the firm's sole representative in Jersey throughout the war. He later became a teacher on the island. After he retired he was involved in Jersey's youth volunteer work in developing countries, and in helping to look after people from Kenya and other places who had come to Jersey for technical assistance teaching. Le Sueur travelled in South America, Eastern and Southern Africa and South-East Asia.