St. John the Baptist was a common subject among academic sculptors of the late 19th Century. Rodin's interest in this subject, however, stemmed from his encounter with an Italian peasant who entered his studio seeking work as a model. The man's rugged physique and awkward, unpracticed manner in posing suggested the blunt, prophetic character of the evangelist. In order to avoid the accusations that had been leveled against his Age d'Airain, 1875-1876, which his detractors claimed had been cast from life, Rodin decided to execute his St. John larger than life.

He modeled a realistic figure, but rather than depicting the action of walking in a conventional manner, showing one foot on the ground and the other raised, he had his model place both feet on the ground, and suggested forward movement by giving him the appearance of leaning forward and beckoning to the viewer. In this manner Rodin depicts consecutive movement in the same pose, breaking the academic tradition of stiff, fixed poses.