Originally called Paramessu, he was of non-royal birth, born into a noble family from the Nile delta region, perhaps near the former Hyskos capital Avaris. He was a career soldier, originally the chief of the archers (a position he inherited from his father, Seti) and ultimately general of the armies. He found favor with Horemheb, the last pharaoh of the tumultuous 18th dynasty, who appointed him his vizier. He also served as the High Priest of Amun – as such, he would have played an important role in the restoration of the old region following the Amarna heresy of a generation earlier under Akhenaten.
Horemheb himself had been a noble from outside the immediate royal family, who rose through the ranks of the Egyptian army to serve as royal advisor and, ultimately, pharaoh; having no son of his own to continue his lineage, in the final years of his reign he named Ramses his coregent and, implicitly, his heir.
Already an old man when he was crowned, Ramses appointed his son, the later Seti I to serve as his coregent. Seti undertook military operations – in particular, an attempt to recoup Egypt's lost possessions in Syria. Ramses appears to have taken charge of domestic matters: most memorably, he completed the second pylon at Karnak, begun under his predecessor.
Dead after ruling for a brief period of 16 months, he was succeeded by his son and coregent. Ramses was buried in Thebes's Valley of the Kings. His tomb there, rediscovered by Giovanni Belzoni in 1817 AD and designated KV16, is small and gives the impression of having been completed hastily.