Who was the father of Gilgamesh?

The traditional father of Gilgamesh is Lugalbanda.

Lugalbanda was a legendary and later deified king of Uruk. In the Gilgamesh tradition, he is paired with the goddess Ninsun, Gilgamesh’s mother. Gilgamesh invokes both parents in earlier Sumerian poems, calling himself the son of holy Lugalbanda and Ninsun. In the Akkadian epic, Lugalbanda also appears as Gilgamesh’s personal tutelary deity, showing how family tradition and divine patronage overlap.

Lugalbanda is important in his own right. Sumerian stories portray him as a soldier in King Enmerkar’s expedition against Aratta. In “Lugalbanda in the Mountain Cave,” he is abandoned while seriously ill, prays to the gods, recovers, and survives through courage and divine aid. The Sumerian King List later places him among Uruk’s rulers and assigns him an impossibly long reign of 1,200 years.

The genealogy is traditional rather than securely historical. Gilgamesh may preserve the memory of a real early king, but Lugalbanda’s historicity is uncertain. Some sources vary: the Sumerian King List gives Gilgamesh a vague or “phantom” father, and a Hittite adaptation omits Lugalbanda. Even so, Lugalbanda is the standard answer for this question.