William Wilson was born in Preston in the last quarter of 1921. His father was William (Willie) Wilson (b. 1884 in Bury), a police officer. His mother was Mary Alice Pownall (b. 1884 in Bickerstaffe, near Ormskirk). Willie and Mary Alice were married in 1909. Willie served 12 years in the army (East Lancashire Regiment, 1902-1914) before becoming a policeman. The couple had 5 children, though one died in infancy. The survivors were: Sarah (Sadie) (b. 1909), Kathleen (b. 1911), Albert (b. 1913) and finally William jnr. The family moved to the Lostock Hall area after the First World War and in 1939, they were living at “Kirby” on Chain House Lane. By this time, Willie had retired from the police force and was working as a watchman though he was also still in the Police Reserve.

William turned 18 just after War was declared. He enlisted with the RAF Volunteer Reserve and was assigned service number 131875. He was posted to 612 Squadron.

In August 1942 the squadron returned to the UK from a brief period in Iceland and was based at Thorney Island, where it prepared for a new role as an anti-shipping squadron. Operations began in September and the squadron's area of operations spread from Cherbourg to Le Havre. By the end of September the squadron had been withdrawn from the bombing campaign and returned to the north of Scotland, where it flew a mix of anti-submarine patrols and convoy protection missions, focusing on the precious convoys to Russia.

At the end of 1942, William was granted home leave and he married Alice Hunt (b. 1921 in New Longton), a shorthand typist.

Towards the end of 1942 the squadron began operations off the Norwegian coast but in April-May 1943 they moved to Davidstow Moor (Cornwall) and began to fly the Wellington Mk XIV, which specialised in anti-submarine warfare. For the rest of 1943 and the early months of 1944 the squadron focused on night sorties over the Bay of  Biscay, hoping to attack German U-boats as they were crossing the bay.