Horemheb was born a commoner, probably at Herakleopolis, a city on the west bank of the Nile near the entrance to the Faiyum, where the local god was Horus of Hnes. His parentage is unknown, but his coronation text credits Horus of Hnes with establishing him on the throne, suggesting that his hometown remained central to his identity even after he became pharaoh. He began his career not as a soldier but as a scribe, the profession that trained Egypt's administrators in reading, writing, and law, and from there he entered the military and rose through the ranks with a speed that testified to both his competence and his ambition. By the time Akhenaten moved the capital to Akhetaten, the Horizon of the Aten, Horemheb was already serving in the army, and under Tutankhamun he became commander-in-chief of all Egypt's forces, the highest military office in the land.

His titles, carved on the walls of the tomb he built for himself at Saqqara while he was still only an official, read like a catalogue of power: Hereditary Prince, Fan-bearer on the Right Side of the King, Chief Commander of the Army, King's Messenger in front of his army to the foreign countries of the south and the north, and Sole Companion, he who is by the feet of his lord on the battlefield on that day of killing Asiatics. The tomb itself was a monument fit for a king: a vast complex with courtyards, chapels, and pylons, decorated with reliefs showing Horemheb receiving the Gold of Honour from Tutankhamun and leading diplomatic missions to Nubia. He was, by every measure, the most powerful man in Egypt after the pharaoh himself.

When Tutankhamun died without an heir around 1323 BCE, Horemheb expected to succeed him. He had been the boy king's chief military advisor, possibly his regent, and he had overseen the restoration of the old gods after Akhenaten's revolution. But Ay, the elderly vizier who had served Akhenaten and then Tutankhamun, moved faster. Ay married Ankhesenamun, Tutankhamun's widow, performed the Opening of the Mouth ceremony on the boy king's mummy, and claimed the throne for himself. Worse, Ay named his own general, Nakhtmin, as Crown Prince and "King's Son," sidelining Horemheb entirely. Horemheb, then in the north leading armies against the Hittites, the empire that dominated Anatolia and threatened Egypt's Syrian possessions, could do nothing. He kept his military power and waited.

Ay reigned for only four years before dying of natural causes. When he did, Horemheb struck. He seized the throne by force, presumably backed by the army that had been loyal to him for decades, and began a campaign of retribution that would define his reign. Nakhtmin vanished from history; his statues were smashed to fragments and his name erased from every record. Ay's tomb, WV23 in the Western Valley of the Kings, was desecrated: the sarcophagus was smashed, the cartouches chiselled from the walls, and the mummy probably destroyed. Horemheb usurped Ay's mortuary temple at Medinet Habu, carving his own name over Ay's inscriptions, and seized a seventeen-foot colossal statue that Ay had already usurped from Tutankhamun, erasing both their names and carving his own titulary in their place. The message was not merely political. It was personal.

But Horemheb's vengeance was not indiscriminate. He spared Tutankhamun's tomb from vandalism, perhaps out of respect for the king who had raised him to prominence, perhaps because Tutankhamun had died too young to be a true rival. Instead, he usurped Tutankhamun's monuments - statues, wall reliefs, even the Colonnade Hall of Luxor Temple - replacing the boy king's name with his own wherever the stone was still serviceable. The monuments of Akhenaten were treated more harshly: the temples of the Aten at Karnak were dismantled, their talatat blocks reused as rubble fill in Horemheb's new pylons, and the heretic's name was hacked from every surface that bore it. In the Abydos king list, carved during the reign of Seti I of the Nineteenth Dynasty, the names of Akhenaten, Smenkhkare, Neferneferuaten, Tutankhamun, and Ay were simply omitted, and their combined reigns were subsumed under Horemheb's. For a time, it seemed as though the Amarna Period had never happened.

As pharaoh, Horemheb proved to be more than a destroyer. He was a reformer. The Great Edict, a stela erected at the base of the tenth pylon at Karnak, laid out a comprehensive programme to restore maat, the cosmic order and justice that Akhenaten's revolution had disrupted. He appointed judges and regional tribunes, reintroduced local religious authorities, and divided legal power between the viziers of Thebes and Memphis. He cracked down on corruption among tax collectors and officials, reformed the labour system at Deir el-Medina, the village where the artisans who built the royal tombs lived, and launched military campaigns to reassert Egyptian control over southern Canaan and Nubia. He married Mutnodjmet, who may have been the younger sister of Nefertiti, the most beautiful queen Egypt had ever known, and the daughter of Ay himself, a marriage that connected him to the royal bloodline he had otherwise tried to erase.

Horemheb died after a reign of twenty-seven years, around 1292 BCE, without a surviving son. His queen Mutnodjmet had given birth several times but none of the children lived, and she was buried with a baby at her side, perhaps dying in childbirth. Horemheb chose his vizier Paramessu as his successor, a man from the eastern Delta who took the throne as Ramesses I and founded the Nineteenth Dynasty. The new dynasty regarded Horemheb as its spiritual ancestor, and Ramesses I's son, Seti I, and grandson, Ramesses II, the great builder pharaoh who would rule for sixty-six years, continued his policies of restoration and expansion. Horemheb was buried in tomb KV57 in the Valley of the Kings, a tomb with stepped corridors and polychrome bas-reliefs that included the earliest known version of the Book of Gates, a funerary text that guided the dead through the underworld. The tomb had been looted in antiquity and damaged by floods, but fragments of his mummy may still lie within.