William Thomas Klersy DSO DFC (2) was born at Brantford, Ontario (ON). On June 28, 1941, he enlisted in the RCAF in Toronto ON.

After receiving air crew instruction at various training schools in Canada, Klersy graduated as a pilot on July 4, 1942 from No. 6 Service Flying Training School at Dunnville ON. After graduation he was retained in Canada and posted to No 130 Squadron at Bagotville, Quebec, for home defence duties.

On July 1, 1943, he arrived overseas in the UK and was posted to Redhill, Surrey, flying Spitfire VBs for medium altitude bomber escort duty. In March 1944, the squadron was re-equipped with Spitfire Mark IX Bs. By the end of July 1944, Klersy had destroyed several enemy aircraft and was awarded the Distinguished Flying Cross (DFC) for his skill and gallantry.

By September 17, 1944 his first tour of duty ended and he was assigned staff duty at RCAF Headquarters. After the Commanding Officer of 401 Squadron was shot down on Christmas day, Klersy was give command of his old unit (401), then based at Heesch in Holland.

By December 1944, he had destroyed seven enemy aircraft and was awarded his second DFC. By May 4, 1945, Klersy flew his final operational mission. By that time he had accumulated a score of 16 and one half enemy aircraft destroyed and three and one half damaged.

Between the Battle of Britain and V-E Day, May 1945, No. 401 (initially No.1) Squadron, had destroyed 195 enemy aircraft, probably destroyed another 35 and damaged 104 enemy planes. Klersy had emerged as the highest scoring ace in the squadron.

In June 1945 Klersy was awarded the Distinguished Service Order (DSO) for his skill and achievements. His citation reads as follows:

"Throughout two tours of operational duty, S/L Klersy has displayed outstanding leadership, courage and devotion to duty. Since the award of a Bar to the Distinguished Flying Cross, he has destroyed or further damaged 90 enemy vehicles, 8 locomotives and 8 goods trucks.

He has also destroyed three more enemy aircraft, bringing his total to at least 10 enemy aircraft destroyed. This officer has moulded his squadron into a powerful operational unit that, by maintaining a consistently high standard in every phase of ground or air activity, has set a magnificent example to the rest of the Wing."

On May 22, 1945 while on a flight to London, he flew his Spitfire into a cloud layer, something went wrong and he crashed into a hill near Wesel in Germany and perished.