Kitano attained his medical doctor degree in 1919 and then became a lieutenant as an army surgeon. He later went to Manchu School of Medicine in Manchuria. In 1936, he became a professor in microbiology. In 1942, Kitano was appointed the second in command for Unit 731 and also the head of biological experimentation. In 1945, he was appointed the commander of the Thirteenth Army Medical Corps.
Encounter with the United States
Like Shiro Ishii, Masaji Kitano was granted immunity from prosecution by the United States. He then worked for the Japanese pharmaceutical company Green Cross, becoming the chief director of the company in 1959.