Robert William Rouviere Day DFC was born in Victoria, British Columbia (B.C.) and was employed by his father's insurance company, before WW2. In January 1940, Day enlisted in the RCAF in Vancouver, B.C. He received air crew instruction at training schools in Canada.

In July 1940, Pilot Officer Day graduated as a pilot from No. 1 Service Flying Training School and in September 1940 was promoted to Flying Officer. From October 1940 to October 1942 Day was engaged in Flying Instruction duties and in June 1942 had been promoted to Flight Lieutenant. In November 1942 Day arrived in the UK.

Between February 1943 and October 1943 he served with Nos. 402, 412, 416 and 421 Squadrons, flying Spitfires most of the time. In December 1943 he arrived in Bombay, India. He was first posted to No. 81 Squadron, flying Spitfires, where he served from December 11, 1943 to August 19, 1944.

Day flew missions with No. 67 Squadron from December 18, 1944 to February 21, 1945. By that time, he had flown 385 operational hours and 285 missions accounting for at least five enemy aircraft destroyed. He had been promoted to Squadron Leader in August 1944. For his skill and bravery he was awarded the Distinguished Flying Cross (DFC) effective March 27, 1945.

His citation reads as follows; Squadron Leader Day is a most determined and resolute fighter. He has completed a large number of sorties and has invariably displayed the greatest keenness. In January 1945, Squadron Leader Day led a section of four aircraft in an engagement against six Japanese aircraft. Five of the latter were shot down, two of them by Squadron Leader Day. This officer has shot down at least five enemy aircraft.

Squadron Leader Day was released from the RCAF on November 21, 1945.