419 Squadron was initially formed at 419 Mildenhall, Suffolk, England, in 1941 as part of 3 Group RAF Bomber Command. The squadron participated in numerous missions while flying Wellington, Halifax and Lancaster bombers. During 419's World War II period, the members of the squadron distinguished themselves despite being subjected to one of the worst casualty rates of any squadron in Bomber Command. This record of achievement is epitomized by P/O A.C. Mynarski who was posthumously awarded the Victoria Cross for his actions during an operation over Cambrai on 12/13 June 1944; only one other member of the KCAF was to receive this decoration. After the war in Europe had ended, the squadron's Lancaster were flown back to Canada where the squadron was disbanded in September 1945.
The second era of "Moose" Squadron began with its re-activation on 11 March 1954 at North Bay, Ontario. Designated as an all-weather fighter squadron, the unit was allocated the Avro CF-100 which was to be the only aircraft the squadron would have until it was again disbanded in December 1962. The unit was awarded the Steinhardt Trophy for squadron proficiency, in 1955. In 1957, 419 Squadron was transferred to Baden-Soellingen, West Germany, as part of the NATO forces of Europe.
The beginning of the present 419 Squadron was the No. 1 Canadian Forces Flying Training School (1CFFTS) which began the move to Cold Lake, Alberta, from Gimli, Manitoba, in December 1970. Initially, 1 CFFTS flew the T-33 Silver Star jet trainer, and in 1974 conversion to the CF-5 Freedom Fighter was begun. This latter aircraft is still the aircraft flown by 419. Active duty for the squadron began in November 1975 and the task assigned was the training of pilots who would eventually go on to fly the CF-101 Voodoo, CF-104 Starfighter, CF-5, or CF-18. During 1977, the squadron began to participate in tactical exercises in addition to its training role. In April 1987, 419 Squadron paid its last official visit to 4 Wing, when four CF-5s and approximately 50 "Moose-persons" made the trans-Atlantic crossing to Baden-Soellingen using air-to-air refueling, as part of Exercise "Rhine-Moose".