The squadron was formed on 16 June 1941 at RAF Digby in Lincolnshire, England as an Article XV squadron under the control of the British Royal Air Force. The squadron was equipped with the Supermarine Spitfire and after a period of training the squadron began operations in August 1941 with the Spitfire VB variant. Part of the Hornchurch Wing it operated over continental Europe on Rhubarb sorties and as bomber escorts. After some rest periods the squadron joined the Kenley Wing for more operations over Europe.
Converting to the Spitfire IX in October 1943 it then became a fighter-bomber squadron.  Within two weeks of the D-Day it was operating from France in the close-support role and it also operated armed reconnaissance flights. Following the advancing troops the squadron was soon based in Germany until it was disbanded at Utersen on 21 March 1946.
411 Squadron was reformed as a peacetime reserve fighter squadron at RCAF Station Downsview Ont. just outside Toronto on 1 October 1950. It was known as the 'County of York' squadron the county in which Toronto used to be. With Havards and Chipmunks as trainers the squadron operated the de Havilland Vampire then moved on to the Canadair Sabre made by Canadair in Montreal in the 50s. In the fall of 1958, the 411 switched to being a light transport squadron which flew the Expediter C-45, a version of the Beechcraft Model 18.
The squadron fully moved to a Search and Rescue mode when they gave up their jets and operated twin engine Beechcrafts and then single engine Otters. The DHC-3 Otters operated with the RCAF code 'CSR-123' standing for Canadian Search and Rescue Model 123. The squadron disbanded in 1996 following the closure of RCAF Station Downsview.