The Imperial High Command, which is also referred to as Imperial Command, High Command, or simply IHC, functioned as a key command division within the Galactic Empire. The Supreme Commander, who reported to the Emperor himself, formally oversaw it. The IHC formulated the objectives for the Imperial Military and received daily briefings from the Joint Chiefs, even though Imperial Command's structure placed it beneath them. Its membership included figures from the Admiralty, General Staff, Imperial Security Bureau, Stormtrooper Command, and Battle Station Command.
Once authority passed below the IHC, branch-specific leadership assumed control, leading to a more decentralized organization. At this operational level, decisions were primarily made by the leaders of the three primary branches: the Admiralty, overseeing the Imperial Navy; the General Staff, managing the Imperial Army; and Stormtrooper Command, in charge of the Stormtrooper Corps. From there, command descended from Imperial officers in charge of progressively smaller military units, until the responsibility for combat ultimately rested with the enlisted soldiers and naval troopers.
Following the Battle of Yavin, due to his correct prediction of the first Death Star's vulnerability, Emperor Palpatine temporarily promoted Grand General Cassio Tagge to the position of Supreme Commander.
Darth Vader, the Emperor's right-hand and informal Commander-in-Chief of the Imperial Military, along with Grand Moff Wilhuff Tarkin, Director Orson Callan Krennic of the Imperial Military Department of Advanced Weapons Research, and Grand Admiral Thrawn of the 7th Fleet, also held membership in Imperial Command. It contained at least one sub-unit that was responsible for the development of new strategies and tactics as part of the Empire's five-year plans for the Outer Rim Territories.
The Imperial High Command functioned as a command group within the Galactic Empire. In the wake of the Empire's establishment, the division oversaw the creation of multiple specialized soldier corps. During his time at the Academy for Young Imperials, Zare Leonis, while posing as a model cadet, secretly provided information about Imperial Command to the Spectres. Minister Maketh Tua of Lothal stated that Imperial Command was unable to act against Rebel sympathizers who had influential allies within the Imperial Senate. In 2 BBY, Imperial High Command dispatched Grand Admiral Thrawn to the Imperial Armory Complex on Lothal to investigate a high incidence of defective vehicles, with ISB Agent Kallus being alerted to his imminent arrival. The Chiss naval commander determined that a rebel cell was sabotaging the vehicles and executed agent and laborer Morad Sumar during a demonstration on a 614-AvA speeder bike as an example to the rest of the workers.
In 1 BBY, death trooper commander DT-F16 demanded that Director Orson Krennic and the rest of Imperial Command be notified of the insurgent attack on their kyber-transporting freighter while requesting reinforcements. In 0 BBY, Governor Wilhuff Tarkin oversaw Battle Station Command, wielding complete authority over the Death Star. After the battle station's destruction, Emperor Palpatine granted Grand General Cassio Tagge supreme command; General Tagge was later demoted and executed for one of his oversights. Following the presumed destruction of the Imperial-class Star Destroyer Harbinger by the Rebel Alliance, Lord Vader personally contacted the Star Destroyer's admiral.
The reference book Star Wars Rebels: The Visual Guide provided the first mention of Imperial High Command. Although its position within the Galactic Empire's broader command structure has not been fully clarified in canon, Star Wars (2015) 22 stated that Darth Vader was an Imperial Command member. In the non-canon 2016 Disney XD television series LEGO Star Wars: The Freemaker Adventures episode "Showdown on Hoth," the Imperial officer Plumestriker also briefly mentioned the group.