Twelve years later, he came to be lodged with the now-famous Buddhist poet and nun Ōtagaki Rengetsu, who would become his greatest scholarly mentor and supporter.

In 1861, Tessai opened a private school in Rengetsu's house to teach painting; he went on to become a teacher at the newly inaugurated Ritsumeikan University in 1868.

He also served as a Shinto priest at a number of different shrines, but ultimately resigned from his final post when his brother died, so that he could look after his mother.

After Tessai settled back in Kyoto in 1882, he championed the old styles of Japanese traditional painting against the new influences of Western art (yōga), then becoming more and more popular, and was thus a participant in the early nihonga movement.

Tessai tended towards use of rich colors to portray scenes of people in landscapes, with a composition intended to evoke or illustrate a historical or literary episode.

Tessai's final works either use very brilliant colors, or else were monochrome ink with dense, rough brushwork and occasional slight jarring touches of bright pigments.