The King Stallion is an evolution of the long running CH-53 series of helicopters which has been in continuous service since 1966, and features three up-rated 7,500 shp (5,590 kW) engines, new composite rotor blades, and a wider aircraft cabin than its predecessors.

The Sikorsky CH-53 Sea Stallion came out of the US Marine Corps' (USMC) "Heavy Helicopter Experimental" (HH(X)) competition begun in 1962.

The Air Force's MH-53H/J/M Pave Low were the final twin-engined H-53s, and had extensive avionics upgrades for all-weather operation.

[4] In October 1967, the USMC issued a requirement for a helicopter with a lifting capacity 1.8 times that of the CH-53D, that could fit on amphibious assault ships.

Before this, Sikorsky had been working on an enhancement to the CH-53D, under the company designation "S-80", featuring a third turboshaft engine and a more powerful rotor system.

Sikorsky proposed a new model, originally designated "CH-53X"; in April 2006, the USMC signed a $18.8 billion contract for 156 "CH-53K" helicopters, with deliveries to be completed by 2021.

[28] Major subcontractors include Aurora Flight Sciences (main rotor pylon), Exelis Aerostructures (tail rotor pylon and sponsons), GKN Aerospace (aft transition), Onboard Systems International (external cargo hook), Rockwell Collins (avionics management system), Sanmina-SCI Corporation (communications), and Spirit AeroSystems (cockpit and cabin).

The HEMT is a 3D simulation of multiple scenarios, such as functional test, troubleshoot, fault isolation, removal and installation of 27 subsystems.

[34] The maiden flight was delayed, due to issues with the titanium quill shafts in the transmission and gear box.

[40] On 7 March 2018, one lifted a payload of 36,000 pounds (16,000 kg), the maximum weight on the single center point cargo hook.

[43] In December 2018, the CH-53K was projected to not be combat ready as expected in late 2019, due to delivery delays caused by technical flaws found in testing, which resulted in a major program restructuring.

[45] The CH-53K King Stallion is a heavy lift helicopter, being a general redesign of the preceding CH-53E, the main improvements being the new engines and cockpit layout.

The CH-53K is powered by the General Electric GE38-1B engine,[46] which was selected over the Pratt and Whitney Canada PW150 and a variant of the Rolls-Royce AE 1107C-Liberty used on the V-22 Osprey.

[49] The CH-53K features a new digital glass cockpit with fly-by-wire controls and haptic feedback, HUMS,[50] a new elastomeric hub system, and composite rotor blades to improve "hot and high" performance.

[59][60] The CH-53K is to surpass the capability of its predecessor by carrying nearly 30% more than the CH-53E's external payload of 27,000 lb (12,200 kg) over the same radius of 110 nmi (204 km).

It is a Containerized Flight Training Device (CFTD) built by Lockheed Martin, Sikorsky's parent company.

[62] On 22 April 2022, Lt. General Mark R. Wise, Deputy Commandant for Aviation, declared initial operational capability for the CH-53K.

[63] In August 2015, it formalized a requirement for the CH-53K, listing the type as a "very high priority" item to enable the service to perform missions only the platform is capable of.

[70][71] In August 2023, Sikorsky announced they had been awarded a contract by the US Navy for 35 helicopters at a total cost of $2.77 billion, including eight aircraft for Israel.

[66][67] In February 2018, Sikorsky signed an agreement valued at around €4 billion with Rheinmetall to team up for the German Air Force's CH-53G heavy lift helicopter replacement program, in which the CH-53K competed against the Boeing CH-47 Chinook.

[66][67][75] On 29 September 2020, the German Ministry of Defense cancelled the "Schwerer Transporthubschrauber" (STH) heavy-lifting helicopter program,[76] it having been judged to be too expensive; instead, the CH-53Gs are still to be replaced after reexamining the project.

[77] In 2022, Germany decided to procure the CH-47F Chinook instead, citing interoperability advantages with other European NATO countries—especially the Netherlands—as well as the lower unit cost compared to the CH-53K, which would allow the purchase of more helicopters for the same budget.