From the mid-1920s until the end of World War II, Prince Takamatsu pursued a career in the Japanese Imperial Navy, eventually rising to the rank of captain.

Following the war, the prince became patron or honorary president of various organizations in the fields of international cultural exchange, the arts, sports, and medicine.

Shortly after the wedding, Prince and Princess Takamatsu embarked upon a world tour to Europe and then across the United States so as to strengthen the goodwill and understanding between Japan and those nations.

[1] From the 1930s, Prince Takamatsu expressed grave reservations regarding Japanese aggression in Manchuria and the decision to wage war on the United States.

He also officiated the Honorary President of the Preparatory Committee for founding International Christian University (ICU) located in Mitaka, Tokyo.

[2] In 1975, the Bungei Shunjū literary magazine published a long interview with Takamatsu in which he told of the warning he made to his brother Hirohito after the Battle of Midway when he realized Japan's defeat was inevitable; "I said, we now have to think about how to end the war.

[citation needed] Prince Takamatsu died of lung cancer on 3 February 1987, at the Japanese Red Cross Medical Center (ja, located in Shibuya, Tokyo).

Despite opposition from the entrenched bureaucrats of the Imperial Household Agency, she gave the diary to the magazine Chūōkōron, which published excerpts in 1995.

[citation needed] The diary revealed that Prince Takamatsu bitterly opposed the Kwantung Army's incursions in Manchuria in September 1931, the expansion of the July 1937 Marco Polo Bridge Incident into the Second Sino-Japanese War and in November 1941 warned his brother, Hirohito, that the Imperial Japanese Navy could not sustain hostilities for longer than two years against the United States.