日向國
Uehara was born as Tatsuoka Shinaga in Miyakonojō, Hyūga Province (present-day Miyazaki Prefecture), as the second son a "samurai" in the service of Satsuma Domain. In 1875, he was adopted by the Uehara family, a cadet branch of the Shimazu clan, and changed his name to Uehara Yūsaku. He graduated from the Imperial Japanese Army Academy in 1879 with Akiyama Yoshifuru as one of his classmates, and his speciality was military engineering. In June 1881, he was sent to France for studies on modern military techniques, including fortification and artillery. He was promoted to lieutenant in September 1882 and to captain in June 1885, while still in France. After his return to Japan in December 1885, he served in administrative positions within the Imperial Japanese Army General Staff. In 1889 he was sent as a military attaché to Europe. He was promoted to major in May 1890 and was assigned to the IJA 5th Division, commanded by his father-in-law, General Nozu Michitsura.