Gandalf entered into Middle Earth as one of the Istari, and was deemed the wisest of the order by Galadriel. He has been said to be the person most responsible for Sauron's downfall, laboring nonstop for roughly 2000 years to put an end to his reign. Gandalf was the bearer of Narya, the Ring of Fire, given to him by Cirdan when he arrived in Middle Earth.

Gandalf always held Hobbits near to his heart, and he also held their race in high regard. When Bilbo found the Ring, Gandalf immediately suspected that it was the One Ring, but allowed Bilbo to keep it, for he knew Bilbo to be strong, and innocent: plus he knew no safer place for it, and he dare not be tempted with it himself.

In the year 3001, Gandalf persuaded Bilbo to leave the Ring to Frodo, and shortly thereafter, Gandalf set in motion the Quest of Mount Doom. Gandalf was one of the most important people at the Council of Elrond, because he alone knew the full history of Sauron and the Ring. Although he fell battling the Balrog in Moria, he was sent back to Middle Earth as Gandalf the White to complete his errand.

Aside from aiding Frodo in his journey, Gandalf did many other chief deeds during the War of the Ring, including freeing Theoden from the evil spells of Saruman and Wormtongue, and casting Saruman out and taking over as the head of the White Council. After the War of the Ring Gandalf sailed from the Grey Havens with Elrond, Bilbo, and Frodo. It is believed that he also took his beloved horse, Shadowfax.