Eldest son of Lord Tytos Lannister of Casterly Rock. While still in his teens, Tywin put down uprisings by two of his father's most powerful bannermen, the Reynes of Castamere and the Tarbecks of Tarbeck Hall. He extinguished the two Houses completely (acts depicted in the song "The Rains of Castamere". Tywin was named Hand of the King by the newly-crowned Aerys II Targaryen. Tywin wed his cousin, Lady Joanna of House Lannister.
He became Warden of the West and Lord of Casterly Rock upon his father's death. Lord Tywin was by all accounts an able Hand, credited by many with giving the Seven Kingdoms twenty years of peace and prosperity, though it caused tension between Tywin and an increasingly-paranoid King Aerys II. After the investiture of his eldest son and heir, Ser Jaime, into the Kingsguard, Tywin resigned the Handship and returned to Casterly Rock. During Robert's Rebellion, Lord Tywin ignored calls for support from both rebels and royalists. After the Battle of the Trident, he led a force of roughly 12,000 men to King's Landing, declaring his loyalty to Aerys II. Once the king opened the gates, however, Lord Tywin's forces proceeded to sack the city. Lord Tywin ordered the deaths of Princess Rhaenys Targaryen and Prince Aegon Targaryen, presenting their corpses, draped in cloaks of Lannister crimson, to the victorious Lord Robert Baratheon.
After the arrest of his younger son, Tyrion, by Lady Catelyn Tully Stark, Lord Tywin launched the assualt on the Riverlands which marked some of the earliest battles in the conflict later named the War of the Five Kings. He was named Hand of the King by the small council of his grandson, King Joffrey I Baratheon. Lord Tywin defeated northern forces under the command of Lord Roose Bolton at the Battle of the Green Fork. He sent his son, Tyrion, to King's Landing to serve as acting Hand of the King. For a brief time, Lord Tywin held the castle of Harrenhal. Repulsed by forces led by Ser Edmure Tully when he attempted to move his forces west to confront King Robb I Stark, Lord Tywin instead proceeded to King's Landing, joining forces with a great host under the command of Lord Mace Tyrell of Highgarden. Together, the Lannister and Tyrell armies defeated King Stannis I Baratheon at the Battle of the Blackwater.
Lord Tywin was later murdered in his own privy chamber by his son, Tyrion.