Horton Salm was a Human male from the planet Norval II in the Calaron sector of the Outer Rim Territories who was a military officer of the New Galactic Republic and later on to the Alliance of Nations when he participated in the First Multiverse War. An accomplished pilot, leader, and training commander, he preferred to fly Koensayr Manufacturing BTL Y-wing starfighters over newer models, as he felt that the older craft were more reliable and would get him home in one piece.
By 6.5 ABY (1421 NE), Salm was assigned to the New Republic's Folor Base, training several new starfighter squadrons, including the reformed Rogue Squadron and his own Defender Wing. Despite clashes with Commander Wedge Antilles over Rogue Squadron's lack of discipline, and the presence of Tycho Celchu—a suspected sleeper agent of the Galactic Empire—as the unit's executive officer, Salm and his Defender Wing worked effectively with Rogue Squadron at the battle of Vladet and the First Battle of Borleias. Salm was also one of the officers responsible for devising the plan that would eventually cause the planet Borleias to fall to the New Republic.
Following the liberation of the galactic capital, Coruscant, Salm served as a judge presiding over the trial of Tycho Celchu. Celchu had been charged with treason and the murder of Rogue Squadron pilot Corran Horn during the operation to capture Coruscant. Salm was surprised to learn that Horn was in fact not dead, but had been captured by DirectorYsanne Isard, the ruler of the Empire, and interred aboard the Super Star Destroyer Lusankya. Briefly resuming training duties, Salm was based at the Borleias starfighter training base before returning to active combat with a B-wing assault group for the New Republic's campaign against the Ciutric Hegemony, a former Imperial faction, in 9 ABY (1424 NE).
Salm continued to serve the Alliance's course for freedom of his home galaxy against the tyranny of ht eglactic Empire and the combine for centuries. He was chosen to lead Gray Squadron at the Great Battle of Endor in , surviving the run through the second Death Star's superstructure. Salm continued to command combat units, leading Aggressor Wing through the nine months after Endor, an engagement that saw him promoted to the rank of general. Salm later led the Aggressors during the evacuation of Cultric IV.