[1] He was the son of Eumenes, the brother of Philetaerus, the founder of the Attalid dynasty, and Satyra, daughter of Poseidonius.

In his new possessions, he established garrison posts in the north at the foot of Mount Ida called Philetaireia after his adoptive father, and in the east, northeast of Thyatira near the sources of the river Lycus, called Attaleia after his grandfather, and he extended his control south of the river Caïcus to the Gulf of Cyme as well.

Demonstrating his independence, he began to strike coins with the portrait of Philetaerus, while his predecessor had still depicted Seleucus I Nicator.

[3] Imitating other Hellenistic rulers, a festival in Eumenes' honour, called Eumeneia, was instituted in Pergamon.

Eumenes adopted his first cousin once removed, Attalus I, who succeeded him as ruler of Pergamon.