Hideie's father Naoie was daimyo of Bizen province and initially opposed, but later sided with Oda Nobunaga and Toyotomi Hideyoshi. Naoie died in 1581, and in 1582 Hideie became the head of the Ukita clan. As Hideie was still young, it was Hideie's uncle [Tadaie] who acted as leader of the Ukita army (under Toyotomi Hideyoshi) during the siege of Bitchu Takamatsu Castle in 1582. Nobunaga was assassinated on June 2 of that year, but the siege continued until the castle fell two days later. Hideyoshi raced back to Kyoto, leaving the Ukita clan in charge of Bizen, Mimasaka and newly taken parts of Bitchu provinces. The Ukita were also to keep watch on Mōri Terumoto to the west.