She was born in the year 2907 of the Third Age. She was the daughter of Dírhael and Ivorwen, and a descendent of chieftain Aranarth. Her father at first did not want her to marry Arathorn II, partly because she was at the time younger than customary for marriage, and he also foresaw that Arathorn would have a short life. However Ivorwen persuaded him in the end, saying that Arathorn's short life was a further incentive to have a quick marriage, so that an heir could be born to be their people's leader.
Gilraen's son Aragorn was born in 2931 Third Age, but her husband died two years later. She then brought her son to live in Imladris, later she returned to her people where she died in 3007, aged one-hundred years.
Her words from the books are used in the movie by Elrond and Aragorn: "Ónen i-Estel Edain, ú-chebin estel anim" meaning "I gave Hope (an obvious reference to her son's nickname) to the Dúnedain, I have kept no hope for myself."