At one point, the Overseer was accompanied by three Arquitens-class command cruisers, four Raider-class corvettes, and two Gozanti-class cruisers.
At some point during the Galactic Civil War, the Overseer participated in battles at Pothor and Jeyell.
After the Battle of Endor, the New Republic Defense Fleet initiated a strike on the Imperial dockyards located in orbit above the planet Var-Shaa. The Imperials suffered heavy losses, which included an Imperial Star Destroyer and the entire dockyard. Captain Terisa Kerrill ordered a retreat, but one pilot Titan Leader Captain Varko Grey missed his opportunity to board the Overseer as it jumped to lightspeed, but was later picked up by Imperial reinforcements after the New Republic fleet had gone.
Sometime after the Battle of Var-Shaa, the Overseer was the flagship of a fleet that operated in the Talcene System. During this time, a number of Star Destroyers had been attacked, which came to the attention of Admiral Rae Sloane. Sloane had intelligence that Project Starhawk and Commander Lindon Javes were involved and assigned Kerrill, due to her history with Javes before he defected. Kerrill's forces, including the Overseer, were to hunt down and destroy Project Starhawk.
After the deploying Titan Squadron for the mission to Hosnian Prime, the Overseer participated in an attack on a convoy of the New Republic to gain intelligence data on the location of Project Starhawk. The mission was interrupted by the Imperial-class Star Destroyer Tormentor in the early stages and Captain Kerrill had to step in with the Overseer to deploy shuttles with boarding parties to extract the intelligence from transports that Titan Squadron had disabled. The mission was successful, despite the actions from Captain Amos, and the sector coordinates of Project Starhawk was retrieved from the convoy.
After Desevro, the Overseer was lured into a battle that occurred in the Zavian Abyss, and was ambushed, in an attempt by the New Republic to prevent it from finding Project Starhawk. During the battle, the New Republic revealed their prototype Starhawk-class battleship Starhawk, where it used its powerful tractor beam to grab the Overseer and push it into the large asteroids floating nearby causing damage to the Star Destroyer. However, LT-514 managed to complete a scan of the New Republic convoy's navicomputer, which had the sector and system details for Project Starhawk. Kerrill ordered a retreat and jumped to lightspeed.
Following the damage the Overseer received in the Zavian Abyss, it dropped out of hyperspace in the Remitik system and was forced to seek repairs and munitions from the nearby Imperial , commanded by Colonel Gralm. He denied their request and instead, Gralm ordered Kerrill's forces to help defend the depot from rebel guerrillas. Not happy with this, Kerrill ordered Titan Squadron to patrol the depot and scan for munitions that could be seized. They found baradium in a pair of Zeta-class Heavy Cargo Shuttles. During an attack by the New Republic, the baradium shuttles were remotely-piloted back to the Overseer while Gralm was distracted. Once onboard, the Overseer left the system, leaving behind an angry Gralm.
Admiral Rae Sloane came up with plan to distract the Nadiri fleet by carrying out multiple strikes on various locations, which would hopefully result in the New Republic fleet leaving the Nadiri Dockyards and expose to an attack that Kerrill could take an advantage of. Kerrill ordered Titan Squadron to target Mon Cala in a hit-and-fade strike. The Overseer arrived in the late stage of the battle, where it helped destroy the Silver Coronet.
Following the success of the strike on Mon Cala, the New Republic Defense Fleet were dispersed from the Nadiri Dockyards, leaving it exposed for an assault. The Overseer deployed Titan Squadron, who targeted the shield generators and hangars, to soften the dockyard's defenses, followed up by a Baradium missile assault on the Starhawk, which crippled its hyperdrive. When the Overseer launched a final volley of missiles, it was blocked by the Temperance at the last second, crippling its hyperdrive. With the return of the New Republic fleet, Kerrill ordered the Overseer and Titan Squadron to retreat.
After crippling the Starhawk and the Temperance at the Nadiri Dockyards, the Overseer deployed Titan Squadron to attack General Hera Syndulla's fleet, who had left the dockyards for Chandrila, and were limping their way through Sissubo's debris field. Disused Star Destroyer cores floating in the debris field were used as traps and targeted as waves of corvettes and a Nebulon-B frigate passed through and were destroyed. The remaining New Republic ships changed course into the Ringali Nebula.
After forcing General Syndulla's fleet into the Ringali Nebula, the New Republic forces were cornered nearby the moon Galitan. Admiral Sloane sent reinforcements from her fleet to aid Kerrill's mission to finish off the rebels. The Overseer participated in an attack with Titan Squadron on the the damaged Starhawk, defended by Anvil Squadron. Titan Squadron were able to break through and damage the Starhawks tractor beam core, leading to its certain demise. Imperial defector Lindon Javes arrived to fight but was defeated by one of Titan's pilots. Kerrill, now content with the success of her mission, ordered all Imperial ships to withdraw. While, the rest of Imperial forces remained to mop up the New Republic forces, Titan Squadron went back to the Overseer and they jumped to hyperspace. All other Imperial forces were destroyed when Syndulla sacrificed the Starhawk by crashing it into the moon's exposed core, and the subsequent explosion and shockwave wiped out all their ships.
- Star Wars: Battles that Changed the Galaxy
- Star Wars: Timelines
- Star Wars: The Rise and Fall of the Galactic Empire