土佐藩
Kusunose was born as the eldest son to a samurai family of the Tosa Domain (present day Kōchi Prefecture). He entered the Imperial Japanese Army in December 1880, serving in artillery, and was sent as a military attaché for training in France and Prussia from 1881-1885. After his return to Japan, he served in an artillery battalion of the Imperial Guard of Japan in 1888, and afterwards served in a number of administrative and staff positions within the Imperial Japanese Army General Staff. Kusunose was posted as a resident officer to the Japanese embassy in Saint Petersburg, Russia, from April 1891 to September 1893, and came to be regarded as a leading expert on European affairs.