Pierre-Étienne-Théodore Rousseau was one of the leading artists of the Barbizon School, also called the plein-air (open air) landscape school of painters. Nadar much admired the Barbizon painters and their emphasis on nature, declaring that among them Rousseau "has long exhausted praise." Rousseau's melancholy landscapes displayed a wild and untamed view of nature, seemingly incongruous with the refined figure seen here.
Rousseau stands looking at the camera with a directness not evident in most of Nadar's portraits. The photographer conveys Rousseau's strong, intense character; only the unbuttoned second button on his overcoat suggests any lack of discipline on the part of this sitter.