He had started to frequent the Café Guerbois, and was becoming more deeply influenced by the notions which were creating Impressionism. During the Franco-Prussian war and the period of the Commune, he spent some time in London and was introduced to Durand-Ruel by Pissarro, becoming part of that dealer's stable. In the mean time, his father had lost all his money as a result of the war, and Sisley, with a family to support, was reduced to a state of penury, in which he was to stay until virtually the end of his life.

He now saw himself as a full-time professional painter and part of the Impressionist group, exhibiting with them in 1874, 1876, 1877 and 1882. His work had by this time achieved complete independence from the early influences that had affected him. In the 1870s he produced a remarkable series of landscapes of Argenteuil, where he was living, one of which, The Bridge at Argenteuil 1872 was bought by Manet. Towards the end of the decade Monet was beginning to have a considerable influence on him, and a series of landscape paintings of the area around Paris, including Marly, Bougival and Louveciennes. Floods at Port-Marly shows the way in which his dominant and evident lyricism still respects the demands of the subject-matter. From his early admiration for Corot he retained a passionate interest in the sky, which nearly always dominates his paintings, and also in the effects of snow, the two interests often combining to create a strangely dramatic effect  Snow at Véneux. Naturally different, he did not promote himself in the way that some of his fellow Impressionists did, and it was only towards the end of his life, when he was dying of cancer of the throat, that he received something approaching the recognition he deserved.

Alfred Sisley The Seine at Bougival, 1873