He was born in Tokyo, and like most male members of the imperial family during the Empire of Japan, was groomed to pursue a career in the military from an early age.

On 10 October 1943, Prince Morihiro Higashikuni married seventeen-year-old Shigeko, Princess Teru (9 December 1925 – 23 July 1961), the eldest daughter of Emperor Shōwa and Empress Kōjun, who was widely known by her childhood appellation Teru-no-miya.

The couple had five children, the last three of whom were born after the Higashikuni family was removed from the Imperial Household register:[1] His first wife, former Princess Shigeko, died of cancer in July 1961.

The second marriage produced two children: In October 1947, the Higashikuni and other branches of the Japanese Imperial Family were divested of their titles and privileges during the Allied occupation of Japan and became commoners.

As a commoner, he attempted several unsuccessful business ventures before eventually becoming the chief of the research division of the Hokkaido Colliery & Steamship Company.