A legendary Norse sea-king, the youngest son of Hjörleifr and Hildr the Slender, and brother of Hjörólfr. After years of plundering he returned to Hörðaland, where his stepfather Ásmund had ruled during his absence. Ásmund invited Hálfr and his men to a feast, but at night set the hall on fire. Hálfr woke up and told his men to arm themselves, but in the ensuing clash the king died, along with a great many of his warriors.
Two of Hálfr's warriors — Hrókr the Black and Útsteinn — managed to escape. They later sailed out with an army to Norway, fought a battle with Ásmund, and slew him. Hálfr's son Hjörr then became king.
A kenning for fire is Hálfr's Bane.
- Hálfs saga ok Hálfsrekka.
- Skáldskaparmál, 28.