The Hellcat was the main shipboard fighter of the US Navy for the last two years of the Pacific War. During the Gilbert and Marshall Operations, the raid on Truk, in the Battle of the Philippine Sea and at Leyte Gulf,  the entire fighter complement of the Fast Carrier Force consisted of F6Fs - at Philippine Sea Task Force 58 fielded some 450 fighters,  all of them being F6F-3s,  and at Leyte Gulf,  as Task Force 38,  the Carrier Force was equipped with nearly 550 fighters,  all of them Hellcats. This illustrates the astounding degree of standardisation achieved in the American frontline forces, something made possible only by the vast output of US industry (this standardisation in its turn aiding efficiency in production).

The F6F was ordered for the US Navy after the initial shock of Allied contact with superior Japanese fighters, particularly the Mitsubishi A6M Zero, during the first few months of the Pacific War. As a result of this experience of combat against higher-performance machines the Hellcat's specification required the most powerful engine available.  The prototype X6F-1, a progression from the F4F Wildcat which was then the standard fighter of the Navy, was provided with a 1700hp Wright R-2600 engine, but a month later - on 26 June1942 - it was re-engined with a 2000hp Pratt and Whitney R-2800 (the birth of the F6F therefore coinciding almost exactly with the great carrier Battle of Midway, 4-6 June 1942,   in which its predecessor -  the Grumman F4F Wildcat -  played a critical role).

Production F6F-3s made their first combat flights on 31 August and 1 September1943,  from the carriers Yorktown (CV10), Essex (CV9) and the light carrier Independence.  The Hellcat immediately outclassed its opponents,  having higher speed and rate-of-climb,  being rugged and well-armoured but at the same time very maneuverable for such a large machine,  and carrying a heavy and effective armament of six 0.5-inch Browning machine-guns with a large ammunition supply. The arrival of the F6Fs in late 1943, combined with the deployment of the new Essex and Independence Class carriers, immediately gave the US Pacific Fleet air supremacy wherever the Fast Carrier Force operated.

A total of 2,545 Hellcats were delivered in 1943,  in 1944 no fewer than 6,139,  and in 1945 a further 3,578  -  total production was 12,272 units.

The Hellcat was eventually credited with destroying more than 6,000 Japanese aircraft - 4,947 of these by F6Fs of the USN carrier squadrons (209 of the others by land-based Marine Corps F6Fs, and the remainder by Hellcats of other Allied countries). The F6F's most spectacular exploit was the destruction of more than 160 enemy aircraft in one day - 19 June 1944 - in the Battle of the Philippine Sea,  in the aerial massacre usually known as "The Great Marianas Turkey Shoot."

The F6F was also used extensively as a search aircraft and fighter-bomber,  playing a major and increasing part in strikes on Japanese warships and mercantile shipping in 1944 and 1945.  In this role, and for ground attack,  it could carry up to 2,000 lb. of bombs, or be armed with six 5-inch rockets on underwing pylons.