He came to the throne in 1964 at the death of his father.
His name meant Last king, and he was named so because of a prophesy by Malbeth the Seer:'
- "Arvedui you shall call him, for he will be the last in Arthedain. Though a choice will come to the Dúnedain, and if they take the one that seems less hopeful, then your son will change his name and become king of a great realm. If not, then much sorrow and many lives of men shall pass, until the Dúnedain arise and are united again." — Appendix A: "Gondor and the Heirs of Anárion"
Arvedui married Fíriel, daughter of king Ondoher of Gondor, who was killed in 1944. At Ondoher's death, Arvedui sent messages to Gondor claiming the throne as a direct descendant of Isildur, but he was refused: the Gondorians appointed general Eärnil as King instead.
Arvedui became King of Arthedain soon after, and in 1974 T.A. Angmar attacked again, driving the Dúnedain away. Gondor sent help in the form of a great fleet, but it came too late: Arthedain was destroyed, and Arvedui fled to the Ice-bay of Forochel.
The prophecy became truth, for Arvedui was indeed the last King of Arnor, and likewise the line of the Kings of Gondor also ended with Earnil's son Eärnur. The realms were not reunited until a thousand years later, when Aragorn became King Elessar.