Imagawa Yoshimoto
Ujizane was born in Sunpu Domain; he was the eldest son of Imagawa Yoshimoto. In 1554, he married the daughter of Hōjō Ujiyasu (Lady Hayakawa) as part of the Kai-Sagami-Suruga Alliance. Ujizane inherited family headship in 1558, when his father retired in order to focus his attention on the Imagawa advance into Tōtōmi and Mikawa Provinces. His childhood name was Tetsuomaru (龍王丸).