In 1906 he went to China as a private tutor for the son of Yuan Shikai, the then dominant Chinese politician.
He returned in 1909 and took a position teaching political history and theory in the Faculty of Law at Tokyo Imperial University until 1924.
On his return he began to write articles discussing the problems of implementing democratic government in Japan, such as political corruption and universal suffrage.
Arguably his most significant work, "On the Meaning of Constitutional Government," was written in response to the popular belief in the superiority of the Prussian pattern.
[3] In December 1918, Yoshino joined with others to establish Reimeikai which was a society "to propagate ideas of democracy among the people.