Born in Lausanne, Steinlen studied at the University of Lausanne before taking a job as a designer trainee at a textile mill in Mulhouse in eastern France. His father was a post office servant and an amateur landscape-painter.

In his early twenties, he was still developing his skills as a painter when he and his new wife were encouraged by the painter François Bocion to move to the artistic community in the Montmartre Quarter of Paris. Once there, Steinlen was befriended by the painter Adolphe Willette who introduced him to the artistic crowd at Le Chat Noir that led to his commissions to do poster art for the cabaret owner/entertainer, Aristide Bruant and other commercial enterprises.

His permanent home, Montmartre and its environs, was a favourite subject throughout Steinlen’s life and he often painted scenes of some of the harsher aspects of life in the area. He became famous because of his figures of cats.

Steinlen became a regular contributor to “Le Rire”  and “Gil Blas” magazines and other publications including “L’ Assiette au Beurre.” 

In 1893 he draws for the “Chambard Socialiste” under pseudonym P.P (Petit Pierre) so as to avoid political problems because of his harsh criticisms of societal ills. In 1894 Steinlen was invited to work for the “Simplicissimus” in Munich. In 1917 Steinlen leaves for the Front and publishes in 1918 his World War I drawings. Theophile Steinlen died in 1923 in Paris and was buried in the Cimetière Saint-Vincent in Montmartre.