Born in Edo as Kumejiro Nonaka, Toshikata Mizuno was the son of a master plasterer. At fourteen, Toshikata began his study of ukiyo-e under the tutelage Yoshioshi. The wild antics of the famed ukiyo-e master proved to be too much for Toshikata's father, and the training was cut short. Toshikata went on to study with a variety of teachers: Ryuto Yamada for pottery painting and Western-style painting, Hoshu Shibata for Nanga-style landscapes, as well as Seitei Watanabe and Shoso Mishima.

He further explored Western-style rendering through British magazines, newspapers, and painting reproductions. Later, Toshikata returned to Yoshitoshi's studio. His teacher retained a fondness for the young artist and designated him as his successor. In 1887, through his teacher's recommendation, Toshikata joined the newspaper Yamato shinbun as an illustrator,. He worked at the magazine until 1894. He also produced several lithographs for the literary magazine Shinshosetsu and senso-e (war prints) during the Sino-Japanese war.