Following the Allied encounter of the heavily armoured Tiger I and Panther tanks in the North African campaign, the British Army realised that they needed a new platform for the 17-pounder gun to counter the new threat in anticipation of the planned Liberation of France. One such project was the Sherman VC Firefly, a heavily modified variant of the M4A4. The first batch of Fireflies were assigned to the 21st Army Group just before Operation Overlord on 6 June 1944. As British and Commonwealth forces faced over 70% of German armoured regiments during the landings, the Firefly quickly proved its worth as the only tank that was able to reliably penetrate the frontal hull of the Tigers and Panthers at combat range in Normandy. Because of this, the Germans realised the threat imposed by the new “long-barrelled” Sherman, and therefore marked it as a priority target. In turn, the British started painting the bottom of the gun barrel white in an effort to make the gun appear shorter at range.

The Firefly (Overlord) was introduced in Update "Leviathans" as part of the "Echoes of Overlord" pack. This version of the Sherman Firefly represents the tank during its combat debut in the Normandy campaign, featuring camouflage netting and a painted-over gun barrel in an effort to conceal its true size. It serves a similar role as later-generation up-gunned M4 Sherman variants, providing supporting fire while heavy tanks take the spearhead of the assault. The tank is as manoeuvrable as any other M4 Sherman variant; therefore, gathering speed to flank the opponent is easy. Those who are familiar with other M4 Sherman variants will get used to this tank instantly. While this tank is capable of serving as the frontal spearhead for an assault, it is unable to take many hits, especially when most tanks it commonly faces can easily penetrate it.