Born in 1557 in Dewa Province. His name was Katakura Kagetsuna. After serving Masamune's mother Yoshihime, he became the young Masamune's tutor and mentor. From 1584 when Masamune took the clan leadership, Kagetsuna served as his right arm in the campaigns to dominate Tohoku, contributing both military strategy and diplomacy. He played a key role at the Battle of Suriagehara in 1589 in securing Aizu. For the 1590 Odawara campaign, he strongly persuaded the hesitant Masamune to submit—a decision that saved the Date clan from dispossession. Toyotomi Hideyoshi valued Kagetsuna so highly he offered to take him into direct service, but Kagetsuna refused out of loyalty to Masamune. At Sekigahara (1600) he joined Masamune in the Eastern coalition, checking the Uesugi. After the war he held Shiroishi Castle at 13,000 koku and contributed to building the foundations of the Sendai domain. He died in 1615 at age 58, the same year his son Shigenaga won the epithet "Demon Kojuro" at the Summer Siege of Osaka. The name "Katakura Kojuro" was inherited through his descendants.