Pelendur was Steward to King Ondoher of Gondor. When Ondoher and his sons were slain in a battle with Wainriders, Pelendur became the temporary ruler of Gondor. During this time it fell to Pelendur to choose the next King of Gondor.

With the help of the Council of Gondor, Pelendur choose Eärnil I, Captain of Gondor and a descendent of the Royal House, to be King, instead of Arvedui, Ruler of the North-Kingdom and direct descendent of Isildur.

One of the most influential and powerful Stewards of his time, Pelendur was succeeded by his son, Vorondil. It was decided then that the office of Steward would be hereditary. Vorondil was succeeded by his son, Mardil, who became the first Ruling Steward.