After graduating from Tokyo Foreign Language School, where he specialized in French, he decided to follow in his father’s footsteps by becoming a military man. But while a student at the Nagoya Army Preparatory School he was accused of insubordination toward an officer and was expelled.
In 1906 he was arrested and imprisoned for taking part in the movement to oppose a fare rise for the Tokyo streetcars. Thereafter he was accused of various charges a total of five times and in all spent over three years in jail; it is said that each time he went to jail, he succeeded in mastering a new foreign language.
He went to France in 1923, but was arrested in Paris and put in prison and later expelled from the country and sent back to Japan. In September of the same year occurred the Kanto earthquake that leveled Tokyo and Yokohama. In the panic and confusion that followed, a number of Koreans and left-wing leaders were arrested or massacred. Osugi was among those seized by the military police, and he, his wife ltd Noe, and his nephew, the last a mere boy, were all put to death by an army captain named Amakasu Masahiko.
From his days in Foreign Language School he had been a member of the Heiminsha, the socialist and pacifist organization formed by Kotoku Shusui, Sakai Toshihiko, and others.
Later he attended a lecture given by Kotoku Shusui on the occasion of his return to Japan; Osugi was so impressed that he determined to become a follower of anarchism and published serially in the daily newspaper Heimin Shimbun a translation of Kropotkin’s Appeal to Youth. In conjunction with Arahata Kanson he published a magazine called Kindai Shiso in 1912 and a monthly called Heimin Shimbun in 1914. He also organized the Sanjikarizumu Kenkyukai (Syndicalism Study Society), and produced numerous writings and translations dealing with anarchism, the labor movement, evolutionary theory, and the philosophy of life. He spoke out against bolshevism and exercised a considerable influence over the rising labor movement in Japan in the years following World War One.