The First Battle Group, also called the New Republic First Fleet, served as a primary naval force within the New Republic Defense Fleet. Upon being assigned to safeguard the galactic capital of Coruscant, it gained the monikers Coruscant Home Fleet, Home Guard Fleet, or simply Coruscant Fleet.
As one of the four original fleets activated within the New Republic Defense Fleet following the Battle of Endor in 4 ABY, the New Republic First Fleet engaged in combat during the New Republic liberation campaign against the Galactic Empire and Imperial Warlords under the leadership of Admiral Firmus Nantz.
Following the liberation of Coruscant in 7 ABY, the First Fleet received a permanent assignment to defend the New Republic's capital world starting in 8 ABY. Under the command of Admiral Hiram Drayson, its mission was to protect the headquarters of the New Republic Provisional Council.
During the Thrawn campaign of 9 ABY, Grand Admiral Thrawn attacked the planet Mrisst as a ruse to draw the Coruscant sector fleet away from Coruscant. This tactic left Coruscant vulnerable, enabling Thrawn to initiate the Siege of Coruscant.
As of 16 ABY, the First Fleet remained stationed at Coruscant. Shortly before the Black Fleet Crisis, Chief of State Leia Organa Solo dispatched the fleet to patrol Thunder Alley, relieving the Second Fleet which had been on patrol for an extended period without returning home for resupply or shipyard maintenance.
During the Almanian Uprising in 17 ABY, Dark Jedi Kueller devised a scheme to destroy the Coruscant Fleet by planting bombs within droids intended for service on the fleet's ships. However, pirates stole the droids, and they detonated in Smuggler's Run.
During the Yuuzhan Vong War, the First Fleet was positioned at Fondor to safeguard the strategically important Fondor Shipyards following the First Battle of Obroa-skai. The fleet participated in the Battle of Fondor, where the Yuuzhan Vong destroyed a significant portion of its vessels. Later in the conflict, the surviving vessels of the New Republic First Fleet were reorganized into the Galactic Alliance First Fleet.
The Dark Force Rising Sourcebook initially mentioned the Home Guard Fleet as the New Republic's defense force for Coruscant. The novel Before the Storm then introduced the First Fleet and the Coruscant Home Fleet. Despite depicting the First Fleet as Coruscant's defender, the novel did not explicitly connect it to the Coruscant Home Fleet. The Complete Star Wars Encyclopedia later established the First Fleet's identity as the Coruscant home guard. The Essential Guide to Warfare subsequently confirmed the First Fleet's permanent assignment to Coruscant's defense post-liberation.