Born in 1568 as the eldest son of Date Sanetsuna, younger brother of Terumune, making him Masamune's cousin. Raised together from childhood, the two shared a bond closer than brothers. Feared as "Demon Shigezane," he was the fiercest general the Date clan produced. He led the vanguard at the decisive Battle of Suriagehara in 1589 and contributed more than anyone else to Masamune's conquest of Tohoku. He also participated in suppressing the Kasai-Osaki Uprising in 1591. Around 1595, however, a serious rift with Masamune led to his sudden departure from service—some accounts suggest it involved a Toyotomi offer to set him up as an independent lord. After nine years of estrangement he was permitted to return in 1604 and resumed his role as Masamune's right arm. Within the Sendai domain he held 18,000 koku at Watari, founding the Watari Date branch. More than a warrior, he also possessed literary intelligence and authored the "Date Shigezane-ki," a chronicle of the Date clan's battles and Masamune's conduct that remains a primary historical source. He died in 1646 at age 79.

Not merely fierce but also thoughtful and principled. His loyalty to Masamune ran deep—even after leaving service he returned to support his lord. His authorship of a historical chronicle shows intelligence and a keen sense of legacy.

Founder of the Watari Date branch, one of the key sub-domains of Sendai. His valor was second to none in the Date clan, and his battlefield contributions were vital to their rapid expansion. His chronicle remains an important primary source for Date clan history.