The Army existed as far back as 4000 BBY. At some point, the Army established a military academy on the planet Carida. Maintenance of the Armies along with the Republic Navy was handled by the Minister of Defense in the aftermath of the Great Hyperspace War. Following that time, Brigadiers of the Republic Armies were known to have participated in the Great Sith War. At the start of the Mandalorian Wars, there were multiple armies in different sectors of the galaxy. They were only united under one banner when Supreme Chancellor Tol Cressa named Revan commander of the Republic's military forces. A large number of these soldiers later turned traitor and became Sith troopers when Darth Revan, the hero of the Mandalorian Wars, returned from the Unknown Regions and formed a Sith Empire. These former Republic soldiers were heavily involved in the Jedi Civil War and the resultant Dark Wars. The new unified Republic Army later served to combat the reborn Sith Empire that instigated the Great Galactic War and also continued to protect the Republic's reduced territory in the Cold War that followed the conflict.
The Republic Army was heavily engaged in the New Sith Wars from 2000 to 1000 BBY. The Army suffered one of the worst defeats in its history in 1466 BBY when the New Sith crushed Republic and Jedi forces in the Battle of Mizra. This bloody conflict was later immortalized by the poet Felloux. Over five hundred thousand soldiers died in the battle and hundreds of Jedi converted to the Dark Side. Around 1010 BBY, during the last years of the New Sith Wars, the Republic Army was incorporated into the Jedi-led Army of Light under the command of Lord Hoth. In a gruelling campaign on the planet Ruusan, the Army of Light slowly ground down the Sith Brotherhood of Darkness until it finally achieved a costly victory at the Seventh Battle of Ruusan.
Following the end of the New Sith Wars in 1000 BBY, the Ruusan Reformation eliminated the Republic's military, with only a few remaining ground military units were placed under the jurisdiction of the Judicial Forces. The Republic came to rely more heavily on Jedi Knights and local Planetary Security Forces for keeping peace in the galaxy. In 44 BBY during the Stark Hyperspace War, Ranulph Tarkin tried to portray the ground forces of his fleet as the legitimate Republic Army, even referring to it as such. In the final years of the Republic, the Army had degenerated into a poorly trained police force that simply wore fancy uniforms.
At the time of the Separatist Crisis, a number of militarist senators pushed for the passage of the Military Creation Act, a legislative bill that would reconstitute the Republic Army and Navy as a pan-galactic military force. When the Senate learned of the Separatists' plot to gain independence via military force, the Republic Army was reestablished for the first time in a millennium. However, the Republic also authorized the establishment of another branch of the military, an army of clone troopers known as the Grand Army of the Republic.
The Grand Army of the Republic was a major branch of the Galactic Republic Military composed entirely of clone troopers, an army of elite soldiers created from the genetically altered template of the Mandalorian bounty hunter Jango Fett.
The Republic's armies also contained non-clone units. Though most HoloNet-documented battles were fought by the all-clone Grand Army and their Jedi officers during the Clone Wars, the non-clone Republic Army engaged in many battles throughout the galaxy without the aid of a single clone trooper. While clone and non-clone units sometimes served side by side, coordinating the two proved difficult; with the exception of Republic officers who were assigned to lead clone units, most non-clone troops served in the Planetary Security Forces (which were largely used in defensive deployments), or with the Judicials.
During the war, Judicial Terrinald Screed voiced his opinion on the HoloNet that the Republic Army and Navy should fall under a unified command directed from Coruscant, an idea that was realized by the Republic's successor state, the Galactic Empire. Under the New Order, the Republic Army was reformed into the Imperial Army while the clone troopers were reorganized into the Stormtrooper Corps. Many elements of the Republic Army, such as the Special Missions units, were adopted by the Imperial Army and expanded to create a much more formidable military force.
As the early Republic Armies consisted of local militias and mercenaries with no true command in place, its generals often received orders straight from the Republic Defense Ministry, and no single surface marshal coordinated or directed its operations. This often left individual army units ultimately under the control of the Republic Navy and led to many soldiers being stationed more on their starships than on planetary surfaces. This meant that in wartime scenarios, members of the Republic Armies tended to be in transit aboard starships rather than stationed on planets.
The chaotic nature of this piecemeal formation meant that there was no uniformity within the Republic Armies, and not all of its individual units were created equally. In fact, units did not possess any uniform designation but rather their original nomenclatures. Its structure tended to possess both local and historical eccentricities though there were elements common amongst the various military divisions. Each Army division was associated with particular places or beings. For example, a division raised on Coruscant might adopt (or be given) that name as part of its title thereby becoming the "Coruscant Division". One part of the Republic Army that outlived the rest was the Academy of Carida, which served as one of its officer training schools.
This meant that the Armies exerted very little in the terms of political influence in the Republic. Despite this, the Navy showed little desire to incorporate the Armies units and incorporate them as marines with themselves as the controlling body. This tended to form a sometimes violent cultural clash between the two divisions but also meant that the biggest expense faced by the Army such as the movement of their vehicles was placed on the Navy's budget.
With pay and conditions being far worse than those of the Navy, the Army surface units tended to suffer from severe recruitment problems. In order to combat this problem, the Republic began contracting any existing local militias or even mercenary units, sometimes buying them out entirely. A further incentive for dangerous assignments was the offer of healthy signing bonuses for those that accepted entry into the Republic Armies. Though service was not compulsory, it was known that the irregular units tended to make use of recruiting methods that the Defense Ministry did not want to know about.
After the Jedi Civil War, the reliance on Jedi and the critical shortcomings of the Armies led to prioritization of a reliable unified military. The Republic Army had become fully integrated and professional by the time of the Cold War, with the Personnel Division of the Army of the Galactic Republic being an army-wide organization responsible for staff issues, and the Republic Special Forces Division being responsible for Special Operations. A logistical network was established to provide the Army with constant support and reinforcements.
The Army suffered on a financial level during the last years of the Old Republic, which had a detriment on the procurement of equipment at the time. A common factor that the Republic Armies suffered from was its reliance on the Navy for not only transportation but orbital support though only lip service was ever provided in times of conflict. In addition, the Navy often jealously withheld the support of its starfighter squadrons, which denied the Army the capacity to maintain an orbit free of enemy fighters after the fleet had left.
During the era of the war against the Mandalorians, it was officially believed that there was no rank of lieutenant, captain or colonel present within the Armies in order to prevent any confusion with the Naval positions. However, on a vestigial level, it existed amongst the irregular native units along with a number of stranger titles including commandant, Gray Chieftain and Grand Xenog.
The Armies were divided according to local historical structure, but common structures were:
- : consisting of 8 to 12 infantry that were led by both a sergeant and a corporal.
- : consisting of 25 to 40 squads that were led by a Major.
- : ranging between four and nine battalions that had the capacity to hold from 1,000 to 5,000 soldiers. It was led by a brigadier with its own headquarters unit with their mission roles involving large-scale landing operations as well as raids and occupation with their command and control being directed from Navy vessels if present.
- : these consisted of all forces present in the region and were named after the planet which served as their headquarters. A general served as its leader though they simply just directed the orders from the Defense Ministry to the individual brigadiers.
The Republic Army in the Great Galactic War had established a permanent command structure:
- : 2 Troops.
- : 6-10 Troops.
- : 50-100 Troops.
- : 150-250 Troops.
- : 750-1,500 Troops.
- : 4,000-6,000 Troops.
- : 20,000-40,000 Troops. Divisions were the largest force that can typically deployed by a fleet, thus the largest unit generally used in operations.
- : 40,000+ Troops. Task Forces were temporary groupings of Divisions formed when a single division is inadequate.
In the last days of the Republic, there was a clear distinction between combat troops and support as well as command elements within the Army. As such, only the actual soldiers appeared on the battlefield and engaged the enemy, while the command as well as support personnel remained far removed from the actual combat. This meant that it was very rare to see an individual over the rank of lieutenant present in actual blaster combat.
Republic soldiers were decently equipped and supported by several kinds of aerial vehicles. They bore both grenades and blasters. Following the chaos of the Great Sith War, a deliberate decision to reintroduce melee weapons was made. This was brought about by the abundance of lightsaber-wielding opponents. To guard against these weapons, Republic swords were required to be made with a cortosis weave, often of Echani origin. Armor was worn and was noted for its modular nature. One characteristic of the Republic military was its equipping of its personnel with an array of cybernetic implants and head-wear. Some of these were deliberately designed to provide mental protection against the powers of Dark Jedi opponents.
Another trait was its use of specialty equipment, such as the stealth field generator, and also physical enhancement technology. These were non-combat items and saw considerable research and development as a result of the Republic's use. As of the Jedi Civil War, personal shield generators were used. Some models were purchased and some were manufactured directly for the Republic. However, the cost of these devices was such that only small units could be assured of a continual supply. Strike teams favored them as they enabled them to outfight an entire unit with conventional gear. The Republic Army also made use of defensive devices such as turrets and a variety of land mines. This latter item ranged from fragmentation to plasma to toxin, though the first was used more commonly due to how expensive deadly toxins were.
The Republic Army made use of battle droids amongst their forces to augment their fighting potential, with the Sentinel droid being one common version used for a time.
During the Cold War, Republic infantry soldiers were equipped with lightweight duraplast armor, a blaster rifle, a blaster pistol, and grenades, and carried four days of rations. Rifles of the Republic Army all had integrated grenade launchers, and the rifle could be loaded with a variety of different types of ammunition. Special Forces troopers had access to durasteel and cortosis armor, handheld blaster cannons, and personal shield generators.
The most basic non-specialized trooper in the Republic Army was the Republic soldier, who typically wore full heavy body armor and were armed with blaster rifles during the Galactic Wars. Republic Guards were those soldiers assigned to duty on Republic Navy warships as marines.
The Republic Army maintained a number of special forces units throughout its history. One of the most glamorous and storied elite units was the Rocket-Jumper Elite Advance Unit. The Rocket-Jumpers used jetpacks to penetrate deep into enemy territory, using low-altitude jumps to avoid enemy forces and then setting up airheads – staging areas where follow-up troops and heavy equipment could be shuttled in.
Another special operations unit was the Army Recon Commandos of the Mandalorian Wars. These were descended from mercenary units that were skilled in special missions that required multitasking and were often fitted for a variety of multiple environment specializations. These soldiers were grouped together into reconnaissance squads that were often inserted onto the battlefield in order to gather intelligence on enemy positions. This was not their only purpose as Recon Commandos often engaged tactical control operations as well as were employed to position combat squads. In addition, these soldiers were tasked with covert ops such as sabotage or assisting Jedi who were in the field. Those inducted into the ranks of the Recon Commandos were often extremely busy as their talents were greatly used.
During the Cold War, Republic soldiers went through a grueling eighteen week basic training course, followed by up to twelve months of specialist training.
Ranks within the Mandalorian Wars–era Republic Army included:
- The highest-ranking officers within the Republic military that were deployed in the field. During the age of the Jedi Civil War, these brigadiers were often challenged with adequately supplying their troopers on the battlefield, though certain clever individuals often had their forces live off the land. They were also not noted for their negotiation skills, which was a hindrance in operations that did not require any military action. Some brigadiers sabotaged their own careers in a way that did not harm their troops in order to avoid being promoted to full general and thus being burdened by the responsibilities of that post.
- These field commanders often held the rank of sergeant or corporal and descended from local militia's mercenary groups before they joined the Republic army. This made them the brightest as well as the best officers available. During the time of the Jedi Civil War, these officers were extensively trained in the use of vibroweapons after it was recognized that lightsaber-wielding Sith often targeted these soldiers in order to eliminate their leadership of their units.
- The heart of the Republic's army consisted of squads of army troopers who were kept in close quarters to the point that they considered themselves all friends. Commanders often kept these individuals together to encourage camaraderie and improve the units performance. However, logistical problems at the time led to the Republic Army not recognizing the special skills of individuals troopers and not assigning them to squads that would benefit from their abilities.
The Republic Army during the Cold War utilized ranks of:
"Commander" was not a rank within the Cold War-era Republic Army, but was a traditional honorific used to indicate exceptional respect to veteran officers of superior leadership.
- "The New Republic Campaign: Preparing to Move Beyond the Movies" — Polyhedron 86
- The Jedi Academy Sourcebook
- Star Wars: The Roleplaying Game, Second Edition, Revised and Expanded
- Tales of the Jedi Companion
- "Special Ops: Drop Points" — Star Wars Adventure Journal 14
- Knights of the Old Republic Campaign Guide
- Star Wars: The Old Republic Encyclopedia