Elwing and her brothers were born in a house near Lanthir Lamath and lived their until her father went to Doriath to assume his inheritance as King of Doriath. When the Sons of Fëanor attacked Doriath, all of her immediate family was either killed or lost, but those loyal to her family took Elwing as well as the Silmaril they sought and bore her away to the Havens of Sirion. There, Elwing married Eärendil Azrubêl bore him twin sons, Elrond and Elros.
In the present matter at hand, Elwing was forced to abandon her children when the Sons of Fëanor came for the Silmaril in Elwing's possession. Rather than give it over, she threw herself into the Sea and was transformed into a great white bird. She flew continuously until she found the ship that her husband was sailing on. Then, on behalf of the Elves and Men of Middle-earth, they chose to sail for Valinor in the faint hope that they could make a final plea on behalf of those who suffered under Morgoth.
When they arrived, Elwing chose to accompany her husband onto the shores, even though she knew it might mean her death. While Eärendil journeyed to visit the Valar, Elwing walked the shores, eventually meeting the Elves of Alqualondë. When the Valar eventually agreed to go to war to aide those in Middle-earth, and also decided to give both Eärendil and Elwing the choice of which kindred they would belong. Returning to Middle-earth, Elwing and her husband fought in the War of Wrath and were later slain. The Elves of Alqualondë would later build a white tower in her name and honor.