The Triumph, a Star Destroyer of the Imperial Navy, served under the command of Ysanne Isard, who held the position of Director within Imperial Intelligence. It was one of the two vessels assigned to the defense of Imperial Center against the impending invasion by the forces of the New Republic. After sustaining significant damage, the Mon Remonda succeeded in its capture.
While the specific class of the Triumph remained unconfirmed, Admiral Gial Ackbar had previously indicated that approximately seven Victory-class Star Destroyers were stationed to defend Imperial Center prior to the conflict. Furthermore, reports indicated that both sides engaged in missile exchanges during the battle, a capability not typically associated with Imperial-class Star Destroyers, which supports the theory that the ship was indeed a Victory-class Star Destroyer.
Despite being assigned to protect Imperial Center, the Triumph did not possess a particularly distinguished reputation, nor did its crew. Consequently, Isard selected it, along with the Star Destroyer Monarch, which suffered from a similar lack of prestige, to defend the planet during the Seizure of Coruscant.
Isard's intention was for Coruscant to fall into the hands of the Rebels, with the aim of the New Republic discovering its bacta resources ravaged by an outbreak of the krytos virus. Therefore, it is plausible that Isard anticipated the capture or destruction of both the Triumph and Monarch during the battle. She essentially abandoned them to their fate, opting to relocate the superior Star Destroyers Emperor's Will and Imperator instead.
Early in the engagement, the Triumph endured heavy bombardment from the New Republic Star Destroyers Emancipator and Liberator, leading to the collapse of some of its shields. The captain executed a barrel roll maneuver in an attempt to position the undamaged shields between the Triumph and the Rebel forces. However, after the Mon Calamari Cruiser Home One joined the assault, the remaining shields failed.
Under Admiral Ackbar's command, the Mon Calamari Cruiser Mon Remonda then engaged the Triumph with a barrage of turbolaser and ion cannon fire, inflicting sufficient damage to allow assault shuttles to safely participate in direct attacks against it.
Soon after, the Triumph experienced a power failure and began to drift back into Coruscant's atmosphere. Ackbar instructed Mon Remonda Captain Onoma to employ his tractor beams to pull the Triumph along and accelerate its orbital trajectory to prevent it from decaying. Subsequently, it was captured by the New Republic, shortly before the Monarch also surrendered.
A Victory-class Star Destroyer named Triumph participated in an ambush targeting the Nebulon-B frigate Rehz'nor in the game Star Wars: X-Wing vs. TIE Fighter. While the precise timing and location of this encounter remain unknown, it likely occurred before the Battle of Endor. The Triumph could be forced to retreat by breaching its shields, and there is the possibility of destroying it during the mission. If this is the same Triumph, it can be inferred that, within the Legends continuity, the Triumph successfully escaped to hyperspace, which further supports the idea that the captured Triumph was indeed a Victory-class Star Destroyer.