Gerald Wilkinson was born on 31 January 1909, at Mount Abu, Rajputana, India, the son of Stella and Hugh Wilkinson of the Indian Civil Service. He was educated at Copthorne School and Winchester College, from 1922 to 1928, then studied accountancy, joining the Northern Assurance Company. In 1931 he married (1st) Lorna Davies: they had two children, born 1933 and 1936; then following his divorce from Lorna Wilkinson, he married Mariana Ashforth in 1951.

In 1934 Wilkinson joined Theo H. Davies and Company Limited, of Honolulu, becoming manager of the Philippine branch in 1935, and directing a large expansion and diversification of the company. In about 1940 (or possibly earlier), Wilkinson's career took a new turn, when he reported for M.I.6 from the Philippines on Japanese developments, and in December 1941 he became the Prime Minister's liaison officer with General Douglas MacArthur, Commander-in-Chief of Allied Forces in the South-West Pacific Area. Wilkinson served on the island of Corregidor and in Australia, being promoted to the temporary rank of Lieutenant Colonel. He left the Pacific in 1943 and served with British Security Co-ordination, New York [United States] until 1945. Following the war, Wilkinson returned to the Philippines in 1946 to rebuild the Davies operations, and became President of T. H. Davies and Company, Far East Limited, in 1947, then Chairman of the Board and Chief Executive Officer of T. H. Davies Limited in 1962, with headquarters in Honolulu and Manila.

Wilkinson died in London on 2 July 1965. His awards include: United States Legion of Merit (1943); O.B.E (1945); C.B.E. (1957).