William Courtenay was born in 1896. During the First World War, he fought in a battalion of the Cheshire Regiment at Gallipoli (1915) and Gaza (1917) before transferring to become a pilot in the Royal Flying Corps in 1917; he was consequently a founder-member of the RAF in 1918, which he left the following year. Between the two world wars he became heavily involved in the early development of civil aviation as a journalist and publicist, most notably as Amy Johnson's "right-hand man" after her famous flight to Australia in 1930, later becoming air correspondent of the Evening Standard. He also dabbled in Conservative politics and was at one time a prospective parliamentary candidate; in this capacity he would sometimes speak as a "warm-up act" prior to Winston Churchill's speaking engagements in the 1930s.

In order to help boost American sympathies for the British war effort, the government sent him on a six-months' coast-to-coast lecture tour of the United States in mid-1941, to tell American audiences about the Battle of Britain; while there (with no relevant experience) he bought a 16mm cine camera with a large stock of colour film. He was addressing the Boeing factory workers in Seattle in December 1941 when Pearl Harbor occurred. By this date Courtenay was working for the Sunday Times and Kemsley press; so when, in February 1942, the first large-scale American reinforcements sailed from San Francisco to the Pacific, he accompanied them as a war correspondent for his newspapers.

In this capacity Courtenay was accredited to General MacArthur's headquarters, which he accompanied from Australia, through New Guinea [later Papua New Guinea and part of Indonesia], the Pacific islands and the Philippines, landing in Japan on the first day of the occupation; he was present at the Japanese surrender aboard USS Missouri and visited Hiroshima and Nagasaki about three weeks after their destruction. Throughout this period he was writing for the Sunday Times (officially) and taking large quantities of colour film (unofficially).

After the war, Courtenay put his films to good use by showing them to a wide variety of audiences as the basis of lectures on the Pacific war, while resuming his pre-war role as air correspondent for the Sunday Times and Kemsley press. On his way home from Japan in March 1946, he was present at Churchill's Iron Curtain speech at Fulton, Missouri.

Courtenay received an OBE and the Military Medal. He died in 1960.