He was sent by the government for advanced studies to the University of Lyon in France in 1889, and after receiving a doctorate of law in 1891, he studied for an additional year at the Humboldt University of Berlin in Germany.
On his return, he became embroiled in the Civil Code controversy, and urged the immediate adoption of the code as drawn up by French foreign advisor to the government, Gustave Emile Boissonade. When the adoption of the code was delayed in 1892, he appealed to Prime Minister Itō Hirobumi to establish a committee to prepare the new draft, and was chosen to be a member of the new committee in 1893. Together with Hozumi Nobushige and Tomii Masaaki, he is regarded as the father of Japan's civil law, which was put into effect in 1898.
In 1894, Ume was one of a group of lawyers who established the Tokyo Law School, the forerunner of present-day Hosei University, of which he served as president in 1899.
In 1906, he was asked by Itō to help codify the laws for the Japanese protectorate of Korea. He died in Keijo (Seoul) in 1910, of typhoid fever at the age of 51. He was awarded the Order of the Sacred Treasure (1st class) on his deathbed, one day before he died.