The Joint Chiefs of the Imperial Military functioned as an advisory group, comprised of high-ranking generals, admirals, and other military officers, offering counsel to the Emperor on all matters pertaining to martial affairs. This body included the leaders of the Imperial Army and other senior members of the naval chiefs. Given the nature of their responsibilities, many maintained close working relationships with leading officers from COMPNOR and its subsidiary, the Imperial Security Bureau, Imperial Intelligence, and the Naval Intelligence Agency, along with members of the Imperial Ruling Council.
The Joint Chiefs of the Imperial Military was an advisory panel consisting of highly placed military figures from the various branches of the armed services and intelligence communities, with the duty of guiding the strategic direction of the Imperial Military. Historian Beaumont Kin characterized it as the closest entity to a unified command structure for the entire Galactic Empire's military apparatus, encompassing both the Imperial Navy and Imperial Army. Populated by a range of generals, admirals, and other experienced military officers, the Joint Chiefs served as advisors and informants to the supreme leader and overall military commander, the Galactic Emperor Sheev Palpatine, regarding the military landscape. The Joint Chiefs also provided daily updates to the Supreme Commander, who headed Imperial High Command. The Joint Chiefs also had limited interactions with the later supreme commander of the Imperial fleet, Darth Vader, who delegated the task of making his orders practically achievable to them.
The Joint Chiefs' membership comprised both permanent and rotating representatives, including the Chief of the Imperial Army and the Chief of the Imperial Navy. The council also featured high-ranking officers from the Imperial Army, Navy, the Commission for the Preservation of the New Order, the Imperial Security Bureau, and the Naval Intelligence Agency, in addition to various Moffs.

During the early years of the Galactic Empire, leading figures from various divisions of the Imperial Military convened at a summit held at Raven's Peak on Eriadu. Attendees included Governor Wilhuff Tarkin, General Hurst Romodi of the Imperial Army, Admiral Barton Coburn of the Imperial Navy, Chief Scientist Doctor Royce Hemlock of the Advanced Science Division, and Tarkin’s rival Commander Orson Callan Krennic of the Imperial Weapons Division. This summit served as one of the initial gatherings for the soon-to-be-formed Joint Chiefs, with Tarkin seemingly assuming the role of the almost ever-present leader of the Joint Chiefs.
In 14 BBY, the Joint Chiefs included army leaders such as General Cassio Tagge, and naval chiefs like Vice Admiral Tallatz, Rear Admiral Tiaan Jerjerrod, Admiral Conan Antonio Motti, Admiral Kendal Ozzel, and at least three female Admirals. Intelligence chiefs were also active within the Empire and could be part of the Joint Chiefs. Director Armand Isard of the Commission for the Preservation of the New Order appeared to represent COMPOR, at least in part, at Joint Chiefs meetings. ISB Deputy Director Harus Ison, ISB Colonel Wullf Yularen, Naval Intelligence Agency Deputy Director and Vice Admiral Dodd Rancit, NIA Vice Admiral Terrinald Screed were all also part of the Joint Chiefs, representing their respective organizations.
Even when Tarkin was away from active duty due to his assignment at Sentinel Base in 14 BBY, historian Captain Beaumont Kin included him in his list of Joint Chiefs members from that era in his book, The Rise and Fall of the Galactic Empire. Indeed, Tarkin attended a Joint Chiefs meeting that year during the Berch Teller campaign. While not yet a member, Admiral Nils Tenant was also called in to attend a Joint Chief meeting. Following Berch Teller's campaign, the upper echelons of the Imperial hierarchy underwent restructuring; Rancit was killed for treason, Tenant was appointed to the Joint Chiefs, Yularen became Deputy Director of the NIA, and Ison was promoted into the Ubiqtorate. Motti, Tagge, and others received similar promotions. Tarkin himself was promoted to the newly created rank of Grand Moff by the Emperor. Palpatine further established the Council of Moffs.

In 0 BBY, General Tagge and Admiral Motti remained members of the Joint Chiefs, holding the positions of Chief of the Imperial Army and Chief of the Imperial Navy, respectively. Admiral Ozzel and Jerjerrod also continued as members. Yularen, Tarkin, Chief Siward Cass, General Moradmin Bast, who served as Tarkin's aide on the DS-1 Orbital Battle Station, General Romodi, General Trech Molock, Director Krennic, and Sith warlord Darth Vader, were all members of the Joint Chiefs at that time. As informal Commander-in-Chief with power delegated directly to him by his Sith Master, Galactic Emperor Sheev Palpatine himself, Lord Vader's rank within the Imperial Military was acknowledged by many, and he was referred to as "2" by the military, while Palpatine was "1."
Following the destruction of the Death Star at the Battle of Yavin, the Joint Chiefs experienced significant losses in membership. General Tagge was promoted to Grand General and given the office of supreme commander of the Imperial military. General Romodi also continued his service in the Imperial Army. Lord Vader, who killed General Tagge for his failings after Doctor Cylo's attempted Cylo Hijacking. was elevated by Emperor Palpatine to the position of Supreme Commander of the Imperial Fleet and given personal control over Death Squadron. Admiral Ozzel took command of the Sith Lord's armada, while Jhared Montferrat was added to the Joint Chiefs sometime after Tagge's death, and Jerjerrod, who also got promoted to Moff at some point, was assigned to the DS-2 Death Star II Mobile Battle Station as the Director of Imperial Energy Systems and Commander. With Darth Vader fully occupied with the hunt for the Rebel base, the Joint Chiefs were able to concentrate on other aspects of the war effort, such as disrupting the Alliance's supply chains and ability to sustain its own military effort.
The Joint Chiefs of the Imperial Military consisted of various Imperial officers who wielded considerable power and influence over Imperial military policy and strategy. The body's membership was a mixture of permanent and rotating high-ranking representatives. Governor Wilhuff Tarkin was an ever-present figure within the Joint Chiefs, acting as its chair.
Permanent and rotating members included:
- General Moradmin Bast , [5] Science and Engineering Division [24] — member until his death at the Battle of Yavin [5] in 0 BBY. [9]
- Siward Cass — member until his death at the Battle of Yavin [5] in 0 BBY. [9]
- Admiral Barton Coburn , Imperial Navy— member of the summit on Eriadu [5] in 18 BBY, [25] which shortly thereafter became the Joint Chiefs. [5]
- General Ire Falk , Imperial Army— member by the Battle of Endor [5] in 4 ABY . [9]
- Vice Admiral Corf Ferno , Imperial Navy— member during the reconstruction following the Battle of Yavin [5] in 0 BBY. [9]
- Chief Scientist Doctor Royce Hemlock , Advanced Science Division — member of the summit on Eriadu which soon became the Joint Chiefs until his death in 18 BBY. [5]
- Chairman Armand Isard , Director of COMPNOR — intelligence chief and member [5] by 14 BBY . [26]
- Deputy Director Harus Ison , Imperial Security Bureau — an intelligence chief and member [5] by 14 BBY. [26]
- Moff Tiaan Jerjerrod — member [1] by 14 BBY [26] as a Rear Admiral. Rejoined the Joint Chiefs by the Battle of Endor [5] in 4 ABY until his death that year and battle. [9]
- Commander Orson Callan Krennic , Director of Advanced Weapons Research — member of the summit on Eriadu that soon became the Joint Chiefs [5] until [14] his death in the Battle of Scarif. [27]
- General Trech Molock — member until his death at the Battle of Yavin. [5]
- Admiral Jhared Montferrat , Imperial Navy— member in the years prior to the Battle of Yavin. Rejoined the Joint Chiefs following the Cylo Hijacking during reconstruction. [5]
- Admiral of the Navy Conan Antonio Motti , Imperial Navy— member [1] by 14 BBY [26] as a rear admiral. Continued to serve as Chief of the Imperial Navy until his death in the Battle of Yavin in 0 BBY. [9]
- Fleet Admiral [28] Kendal Ozzel , Imperial Navy— member [1] by 14 BBY [26] as a rear admiral. Rejoined during reconstruction prior to his death in the Battle of Hoth [5] in 3 ABY . [9]
- Fleet Admiral [29] Firmus Piett , Imperial Navy— member by the Battle of Endor [5] in 4 ABY until his death in that year and battle. [9]
- Vice Admiral Dodd Rancit , Naval Intelligence Agency — an intelligence chief and member [1] by 14 BBY. [26]
- General Hurst Romodi , Imperial Army [6] and Science and Engineering Division [24] — member of the summit on Eriadu [5] in 18 BBY, [25] which soon became the Joint Chiefs [5] as an Imperial Army General. [6] Later rejoined the Joint Chiefs by the time of the Battle of Yavin [5] in 0 BBY [9] as a General in the Science and Engineering Division. [24]
- Vice Admiral Terrinald Screed , Naval Intelligence Agency— an intelligence chief and member [1] by 14 BBY. [26]
- Admiral Rae Sloane , Imperial Navy— member by the Battle of Endor [5] in 4 ABY. [9]
- Grand General Cassio Tagge , Imperial Army— member [1] by 14 BBY [26] as a general and Chief of the Imperial Army . Eventually promoted to Grand General and supreme commander of the Imperial military and was responsible for rebuilding the Joint Chiefs following the Battle of Yavin [5] in 0 BBY. [9] Continued to serve until his death following the Cylo Hijacking [5] in 0 ABY . [9]
- Vice Admiral Tallatz , Imperial Navy— member [3] by 14 BBY. [30]
- Grand Moff Wilhuff Tarkin— chair of the committee on Eriadu that soon became the Joint Chiefs [5] in 18 BBY . [25] Member until his death at the Battle of Yavin [5] in 0 BBY . [9]
- Admiral Nils Tenant , Imperial Navy— member [1] by 14 BBY. [26]
- De facto Commander-in-Chief [17] and supreme commander of the Imperial fleet Darth Vader— largely distanced himself from the Joint Chiefs. [5]
- General Maximilian Veers , Imperial Army— member by the Battle of Endor [5] in 4 ABY. [9]
- Colonel Wullf Yularen , Imperial Security Bureau and deputy director of the Naval Intelligence Agency [1] — an intelligence chief and member [5] by 14 BBY. [26] Continued to serve until his death at the Battle of Yavin [5] in 0 BBY. [9]
- Three female naval chiefs who held the rank of Admiral were members [3] by 14 BBY. [30]