Eärnil II was a descendant of King Narmacil II and became the thirty-second King of Gondor. He was the Captain of the Southern Army and a valiant general.

In TA 1944 he met the hostile armies of the Wainriders and their allies from Khand and Near Harad and defeated them in South Ithilien and then in the famous Battle of the Camp, finally driving them into the Dead Marshes.

After the loss of King Ondoher and his two sons, Artamir and Faramir, in TA 1944 in a battle north of Morannon, Gondor remained for a year without an obvious successor to the throne. Deeming the time suitable, Arvedui, heir of King Araphant of Arthedain, claimed the crown of Gondor. Not only was he of high lineage, Isildur being his ancestor, but he was also the husband of Fíriel, daughter of Ondoher.

Yet the Council of Gondor rejected his claim, Pelendur, the Steward of King Ondoher playing a major role in that decision, and they granted the throne to the victorious Eärnil. Eärnil was the son of Siriondil, son of Calimmacil, son of Arciryas brother of Narmacil II.

However, after receiving the crown, Eärnil II sent messages of friendship to Arvedui and promised Gondor’s aid when needed. In the autumn of TA 1973 Arvedui asked for help in the war with the Witch-king of Angmar. Eärnil II sent his son Eärnur north with a great fleet, but they arrived too late, for Arthedain had already been defeated and Arvedui had perished. With the aid of Círdan and other Elf-lords, Eärnur succeeded in defeating the forces of Angmar, but the Witch-king escaped and returned to Mordor to gather the other Nazgûl.

In TA 2000 the Ringwraiths came from Mordor through the Pass of Cirith Ungol and began the siege of Minas Ithil, which they captured in TA 2002, along with the palantír held in that tower. Minas Ithil became their abode afterwards and it was renamed Minas Morgul, The Tower of Sorcery.

Eärnil II ruled Gondor for 98 years (TA 1945 - 2043) and was succeeded by his son Eärnur.