Like almost all Imperial Commissars, Colonel-Commissar Ibram Gaunt was an orphan, a son of an Imperial Guard officer. He was raised and indoctrinated on the Schola Progenium world of Ignatius Cardinal, where he was occasionally visited by his "uncle", General Aldo Dercius of the Jantine Patricians. He learned that his father had been an Imperial Guard hero, but had died and the circumstance were hidden from him.
As a Commissar-Cadet he served under Commissar-General Oktar, gaining full rank status of Commissar at Oktar's death-bed. He served as a political officer with the Hyrkan 8th, from the regiment's foundation to their victory on Balhaut, a world reclaimed by the Imperium during the Sabbat Worlds Crusade. After this victory, Gaunt was granted the additional rank of Colonel, along with command of the three new regiments from the world of Tanith.
While serving with the Hyrkans as a cadet, Gaunt encountered a girl who had been touched by the warp, and upon questioning the girl, he discovered the fate of his father: he had served on a mission on an enemy-held world, but was abandoned by the cowardice of General Dercius and left to die. When circumstance brought Gaunt and his uncle together in the field, Gaunt, now a fully fledged commisar with the Hyrkans, revealed this knowledge to Dercius, and challenged him to an honour duel, using chainswords. While killing Dercius, and avenging his father, Gaunt suffered grievous injuries and has a scar across his stomach. This event earned him the hatred of the Jantine Patricians for some years after, which leads to the first novel, First and Only (Abnett, 1999).
He is much more compassionate than most commissars, and does seem to show concern for his men. He tries to lead through virtue, not terror. This style has drawn anger from some of his superiors.
During the founding of the First, Second and Third Tanith Regiments, Tanith fell to a surprise Chaos attack. Gaunt ordered the forces of Tanith to retreat, depriving them of the chance to fight and die for their home world. The retreat was costly; from three entire regiments there were less than four thousand survivors, and not a single officer of the three regiments made it off Tanith.
While waiting for orders, Gaunt was instrumental in the reorganization of the survivors, reorganizing the men into the Tanith First-and-Only, and promoting the non-commissioned officers and soldiers who had shown initiative and leadership during the retreat and subsequent reorganization to officer positions. The Tanith were ordered to the world of Blackshard, and during their successful first engagement were dubbed "Gaunt's Ghosts", a moniker that would stick with the regiment for the duration of its existence.
Gaunt is considered to be an unconventional but effective leader, slowly winning the devotion and respect of the soldiers who initially hated him for letting their homeworld fall to Chaos without a fight. He is feared among the upper echelons of the Imperium almost as much as he is feared by the forces of Chaos, as he is a model for honour and defiance of corruption in all forms. He is respected by many soldiers and commanders because he leads from the front, attacking the enemy alongside his men. He gained great respect with his men and the new recruits for the Tanith First-and-Only when he killed the Chaos warlord Heritor Asphodel during the battle for Verghast.
However, some would consider his unorthodox approach and rank problematic, as in many ways he fails in his duty as a commissar. His ability as a leader is never questioned, indeed he has been approached for promotion several times, but to assist his duties as a commissar, Victor Hark was introduced to the regiment.
Thus far, up to and including the novel His Last Command, the Tanith First-and-Only have been fighting in the Sabbat Worlds Crusade for approximately ten years. They have seen combat on several worlds, including Fortis Binary, Menazoid Epsilon, Monthax, Verghast, Phantine, Hagia, Herodor and Ancreon Sextus. However, due to the inevitable casualties, and the lack of a homeworld from which to draw new recruits, the regiment is constantly dwindling in size. This fate was held back for a time by the mass-recruitment of survivors from the hive-city of Vervunhive, on Verghast, but even with these reinforcements, it was only a matter of time before the Ghosts shrunk below the size of a feasible military force. To solve this problem, the Tanith First was disbanded and folded into the 81st Belladon Recon under Colonel Wilder to form the 'Eighty-first First'.
Recently, the upper echelon of the Imperium's suspicion and unease with Gaunt's unorthodox command approach had reached a boiling point after his return from his Vermilion-level mission (coded EZ for Extremely Hazardous) on Gereon. Afraid that he and his team were "tainted" during their extended stay on a Chaos held world, and because the Tanith First was folded into the Belladon 81st and technically did not exist any more, many high ranking officials decided to strip Gaunt of his command position and revert him back to his original Commissar status. Gaunt eventually manages to regain command of the Eighty-first First, but only after Wilder grants him field command before sacrificing himself in a heroic rearguard action. Whether or not Gaunt will keep his field command is uncertain.
Gaunt later returns to Gereon, bringing with him the Imperial Liberation forces and finally freeing Gereon from the rule of Chaos. He is ordered to establish contact with the resistance, given his prior experience with them. To do so he has to go into the Untill again, discovering on the way that Mkvenner is dead, being reunited with Surgeon Ana Curth and chopping off Larkin's foot with his power sword. It eventually transpires that the Inquisition wanted him to broker contact with the Partisans in order to exploit the Fauna and Flora of the Untill in the search of a cure for Chaos. Gaunt tells the Inquisitor that it is only through "The Armour of Contempt" that they may resist Chaos, hence the name of the book.
During the defence of the Hinzerhaus on Jago, Gaunt is captured by the Blood Pact and presumed dead, leading Major Elim Rawne to take command of the Ghosts. He is only recover by Mkoll and Eszrah ap Niht on the Deada Waeg while they destroy a Pact command camp, though he has been blinded by the Enemy and is close to death due to the torture that he had suffered. He is featured at the end of the book, being told by Lord General van Voytz that his new augmetic eyes will be the best possible. Gaunts only response is to make van Voytz promise never to hang his men out to dry like that again.