- "For those that remain, there is but one choice. We must fight—to victory, or death—for the Republic!"
- ―Jace Malcom
During the Great Galactic War, Republic troopers were deployed throughout the conflict against the Sith Empire, which had returned from its long periods of exile. These soldiers fought in engagements such as the Battle of Bothawui, where a detachment served under Jedi Master Belth Allusis, who died heroically against the Sith onslaught. Their deaths inspired the Galactic Republic, which had previously been fighting a losing war, and gave it hope due to the heavy losses it inflicted on the Imperial Army. Another squad of troopers also fought in the Battle of Alderaan when the Empire invaded the peaceful world.
The Treaty of Coruscant in 3653 BBY forged an uneasy truce between the defeated Galactic Republic and the ascendant Sith Empire. Anticipating future conflict if the truce collapsed, the Republic military began developing elite Special Forces units to counteract the military might of the Sith. Members of these elite strike teams were selected based on their martial prowess, discipline and morale.
In past millennia, the Jedi Order had participated in the defense of the Republic alongside regular military units. Over the generations, the Republic military had cooperated in military operations and strategy with Jedi. However, following the upsurge of anti-Jedi sentiment following the Sacking of Coruscant, the Jedi had withdrawn to Tython, leading to decreased Jedi presence within the Republic. Such developments led to the increased deployment of regular Republic forces in defending the remaining Republic territories.
They saw extensive service during the Cold War and the following Galactic War and were often deployed in small units to the most dangerous battle zones. Whether operating solo or in groups, the trooper could still be a terrifying opponent to the enemies of the Republic. Such was their reputation that they generated fear even among Sith combatants.
During the course of their career, troopers were able to specialize in different battlefield doctrines.
One specialization adopted by certain troopers was that of the Vanguard. These soldiers went into the battlefield wearing unstoppable advanced heavy armor along with an utterly fearless attitude. They were among the first and best line of defense in the Republic military. They proved to be steadfast warriors who ignored personal risk whilst going into the line of fire in order to divert danger from allies or innocents. In combat, they had a tactical role which was inherently dangerous, though Vanguards had an uncanny survival rate due to their expert defensive tactics along with the equally advanced technology at their disposal.
The other specialization was Commando. These troopers, trained in advanced assault tactics and weaponry, charged into the battlefield with massive blaster cannons to devastate their enemies with overwhelming and brutal firepower. Their high-powered hardware allowed them to dominate the battlefield, where they were equally capable of taking out enemy bunkers with focused firepower or driving back an Imperial assault with concussive bolts. Commandos were able to lay waste to all foes within their range, and many of the greatest victories of the Republic were attributed to the decisive actions of these troopers on the battlefield.
Envisaged by Republic military planners as the most advanced force in the galaxy, Republic troopers were trained and equipped to face a wide variety of foes, environments and situations. Since the Great Galactic War, Republic engineers had developed heavier and more powerful blaster rifles. This trend inspired a galaxy-wide shift towards the use of more versatile arms. Since it took a great deal of strength and skill to operate these weapons, they were rarely used outside the military. Due to extensive action in the Great War and the subsequent Cold War and Galactic War, the Republic military was constantly pushed to design more powerful blaster rifles every year.
Their defensive armor was specially designed to provide maximum protection and flexibility for a wide range of environments. It could withstand anything from laser fire to a bomb blast. 
With training and proper use of these powerful weapons at their disposal, the Republic troopers were an elite force to be reckoned with in combat.
Behind the scenesEdit
In the MMORPG Star Wars: The Old Republic, the path progression tree for the trooper class allows players the option of either choosing a Commando or Vanguard specialty, each having their own armor variations and equipment. The Imperial counterpart for this class is the Bounty Hunter.
- The Old Republic—The Lost Suns 1
- Star Wars: The Old Republic, Threat of Peace (First appearance)
- Star Wars: The Old Republic
- Star Wars: The Old Republic: Rise of the Hutt Cartel
- Star Wars: The Old Republic: Galactic Starfighter
- Star Wars: The Old Republic: Galactic Strongholds
- Star Wars: The Old Republic: Shadow of Revan
- Star Wars: The Old Republic: Knights of the Fallen Empire
- Star Wars: The Old Republic: Knights of the Eternal Throne
- The Art and Making of Star Wars: The Old Republic
- Star Wars: The Old Republic Explorer's Guide
- Star Wars: The Old Republic Encyclopedia
- (as "Republic Trooper")
- (Picture only)