The son of Aragost, Aravorn was born during the time when his grandfather Arahad was Chieftain of the Dúnedain, and was thus a direct heir to the Chieftainship himself. Aravorn would later give the name Arahad to his own son and heir, born after the first Arahad's death. In the year III 2588 Aravorn inherited the Chieftainship from his father at the age of ninety-one (a typical age of inheritance for the long-lived Dúnedain).
Aravorn's decades-long rule was apparently a peaceful one for the Dúnedain west of the Misty Mountains, though not elsewhere in Middle-earth. It was during the early years of Aravorn's rule that KingDáin I of Durin's Folk was slain, and his son Thrór led his people back to Erebor. These troubles of the Dwarves had no direct effect on Aravorn himself, though played a tiny part in series of events that would one day make Aravorn's descendant Aragorn the reuniting King of Gondor and Arnor.
As with all the Chieftains of the Dúnedain, Aravorn's date of birth appears only in The Peoples of Middle-earth (Chapter VII The Heirs of Elendil). It cannot therefore be considered completely reliable.
2
The translation 'black lord' relies on breaking down the name as ara-vorn. It could also be interpreted as ar-avorn, which would mean something like 'steadfast lord', though this derivation is somewhat less certain.