Naohiro was the second son of Nabeshima Naomasa, the 10th daimyō of Saga. On the retirement of his father in 1861, Naohiro was appointed 11th (and final) daimyō of Saga Domain.
With the abolition of the han system, he surrendered his domain to the central government, and departed Japan with his two younger brothers for studies in Great Britain starting 1871.[1] He was appointed plenipotentiary minister to Rome in 1880, and returned to Japan in 1882. During his stay in England, he was appointed as official representative of Japan to the Court of St. James's by the Japanese government. After his return to Japan, he served in various political capacities, including president of the Genrōin, advisor to Emperor Meiji (and later Emperor Taishō), and as a member of the House of Peers. He was created marquis (侯爵, kōshaku)) in the Peerage Act of July 7, 1884.[1] From 1911, he was president of Kokugakuin University.