Galathil is a Sindarin Elf, grandson of Elmo, the youngest of the three Teleri brothers directly descended from Enel and Enelya, Elwë (Elu Thingol), Olwë and Elmo himself. Galathil's father was Galadhon, who lived in Thingol' Court with his parents. Galathil had an older brother, Celeborn, who married Galadriel and left Doriath. Galathil had a daughter, Nimloth, who married Dior, Beren and Lúthien's son. He was killed by the Dwarves when they sacked Doriath.

He lives in Tol Eressëa, though he has visited Alqualondë, where he met Elrond Peredhel. Galathil admires him, but he stays away as he is married with Celebrían. Galathil and his wife are no longer together as she decided to move permanently to Alqualondë.

His mare is called Silra