After his father lost the throne of Athens, Acamas grew up as an exile in Euboea with his brother under the care of Elephenor, a relative by marriage.

He and Diomedes were sent to negotiate the return of Helen before the start of the Trojan War,[5] though Homer ascribes this embassy to Menelaus and Odysseus.

[5] In the war, Acamas fought on the side of the Greeks and was counted among the men inside the Trojan Horse.

[10] Some sources relate of Acamas the story which is more commonly told of his brother Demophon, namely the one of his relationship with Phyllis of Thrace.

[10] The promontory of Acamas in Cyprus, the town of Acamentium in Phrygia, and the Attic tribe Acamantis all derived their names from him.