Cousin of Date Masamune, second-in-command of Sendai-han, eldest son and heir of Date Sanemoto and the daughter of Date Harumune (who were originally uncle and niece). He entered Date Masamune's service from childhood and was later decorated for his role in many of the clan's wars.

In 1595, due to dissatisfaction over reward for the Imjin War, Shigezane left Masamune and fled to Mount Kouya.

In 1600, during the Battle of Sekigahara, Uesugi Kagekatsu offered Shigezane an exorbitant reward to become a vassal of the Uesugi Clan, but he refused, saying "I would never serve a vassal house." (Uesugi Sadazane, the last of the Uesugi Clan bloodline to be lord of Echigo, once wanted to adopted Shigezane's father, but the Date Clan refused. If the adoption had taken place, Shigezane would have become the lord of Echigo after his father, and Kagekatsu, as one of the Nagao Clan, would have been a vassal under Shigezane's service.)

Shigezane returned to Masamune's service in autumn of 1600, and later served in the new Shogunate in important roles.

Shigezane's prowess in battle was acknowledged by various daimyo of the age. (He was called 'Date Shigezane the Brave', and he, along with 'Katakura Kagetsuna the Wise', were named 'the twin jewels of the Date'.) He also wrote a famous history of Date Masamune, called the 'Shigezane Chronicles'.