Designed to replace the earlier F4F Wildcat and to counter the Japanese Mitsubishi A6M Zero, it was the United States Navy's dominant fighter in the second half of the Pacific War.

Powered by a 2,000 hp (1,500 kW) Pratt & Whitney R-2800 Double Wasp, the same powerplant used for both the Corsair and the United States Army Air Forces (USAAF) Republic P-47 Thunderbolt fighters, the F6F was an entirely new design, but it still resembled the Wildcat in many ways.

It subsequently established itself as a rugged, well-designed carrier fighter, which was able to outperform the A6M Zero and help secure air superiority over the Pacific theater.

[13] Throughout early 1942, Leroy Grumman, along with his chief designers Jake Swirbul and Bill Schwendler, worked closely with the U.S. Navy's Bureau of Aeronautics (BuAer) and experienced F4F pilots,[14] to develop the new fighter in such a way that it could counter the Zero's strengths and help gain air dominance in the Pacific Theater of Operations.

[19] In addition, the forward fuselage sloped down slightly to the engine cowling, giving the Hellcat's pilot good visibility.

[20] Based on combat accounts of encounters between the F4F Wildcat and A6M Zero, on 26 April 1942, BuAer directed Grumman to install the more-powerful, 18-cylinder Pratt & Whitney R-2800 Double Wasp radial engine – which was already in use with Chance Vought's Corsair since 1940 – in the second XF6F-1 prototype.

[21] Grumman complied by redesigning and strengthening the F6F airframe to incorporate the 2,000 hp (1,500 kW) R-2800-10, driving a three-bladed Hamilton Standard propeller.

A center-section hardpoint under the fuselage could carry a single 150 US gal (570 L) disposable drop tank, while later aircraft had single bomb racks installed under each wing, inboard of the undercarriage bays; with these and the center-section hard point, late-model F6F-3s could carry a total bomb load in excess of 2,000 lb (910 kg).

[25] The later F6F-3N, first flown in July 1943, was fitted with the AN/APS-6 radar in the fuselage, with the antenna dish in a bulbous fairing mounted on the leading edge of the outer right wing as a development of the AN/APS-4; about 200 F6F-3Ns were built.

[20] The F6F-5 featured several improvements, including a more powerful R-2800-10W engine employing a water-injection system and housed in a slightly more streamlined engine cowling, spring-loaded control tabs on the ailerons, and an improved, clear-view windscreen, with a flat armored-glass front panel replacing the F6F-3's curved plexiglass panel and internal armor glass screen.

[12][20] In addition, the rear fuselage and tail units were strengthened, and apart from some early production aircraft, most of the F6F-5s built were painted in an overall gloss sea-blue finish.

[34] Two XF6F-6s (70188 and 70913) were converted from F6F-5s and used the 18-cylinder 2,100 hp (1,566 kW) Pratt and Whitney R-2800-18W two-stage supercharged radial engine with water injection and driving a Hamilton-Standard four-bladed propeller.

[38] In addition to its good flight qualities, the Hellcat was easy to maintain and had an airframe tough enough to withstand the rigors of routine carrier operations.

The Hellcat first saw action against the Japanese on 1 September 1943, when fighters off USS Independence shot down a Kawanishi H8K "Emily" flying boat.

Even so, the aircraft performed well against the best Japanese opponents with a claimed 13:1 kill ratio against the A6M Zero, 9.5:1 against the Nakajima Ki-84, and 3.7:1 against the Mitsubishi J2M during the last year of the war.

"[47] During the course of World War II, 2,462 F6F Hellcats were lost to all causes – 270 in aerial combat, 553 to antiaircraft ground and shipboard fire, and 341 due to operational causes.

[48] Hamilton McWhorter III, a Navy aviator and a flying ace of World War II, was credited with shooting down 12 Japanese aircraft.

[49] Arthur Van Haren, Jr., a Navy combat Hellcat ace of WWII from Arizona, was credited with shooting down 9 Japanese planes.

1844 Naval Air Squadron, on board HMS Indomitable of the British Pacific Fleet was the highest-scoring unit, with 32.5 kills.

With the cessation of hostilities, the squadron (which included pilot William Stevenson) was disbanded and the Hellcats dumped off the Scottish coast.

[58] The Hellcat was used for second-line USN duties, including training and Naval Reserve squadrons, and a handful were converted to target drones.

These were painted in Gloss Sea Blue, similar to post-World War II US Navy aircraft until about 1955, but had a modified French roundel with an image of an anchor.