In 1902, he served in the House of Peers, and on November 30, 1903 graduated from the 15th class of the Imperial Japanese Army Academy.

Due to his status, he was awarded the rank of major general in the Guards Cavalry Regiment and served with distinction in the Russo-Japanese War.

It is commonly stated that he was standing next to Lieutenant Yoshinaga Nanbu, the 42nd chieftain of the Nanbu clan, during the Battle of Mukden when the latter was hit by a Russian bullet and died in combat; however, this incident occurred on March 4, 1905, after Prince Tsunehisa had been recalled to Japan.

He was wed to Emperor Meiji's sixth daughter Masako, Princess Tsune on April 30, 1908.

Due to his death, the coming-of-age ceremony for his nephew-in-law, Prince Hirohito had to be postponed by one year to 1920.