After spending the first years of his life in the Antilles, Henri Le Sidaner moved to France with his family in 1872. He started studying art in 1877 with the painter Alexandre Desmit in Dunkirk. In 1882 he entered Alexandre Cabanel's studio at the School of Fine Arts in Paris.
From 1882 to 1893, Le Sidaner went to Etaples of which the costal landscape provided him various themes for his works made in open air.
Le Sidaner started to exhibit at the Salon des Artistes Français in 1887. His naturalist works from Etaples had a good reception and allowed him to travel in Italy and Holland in 1891. Three years later he presented Impressionist paintings influenced by Monet at the Société Nationale des Beaux-Arts.
From 1896 until the end of the century, Le Sidaner painted symbolist themes depicting thoughtful women dressed in white in the gardens in the twilight.
From 1900, Le Sidaner rarely describe human figure. He prefered to depict cities such Bruges, Beauvais, Chartre or London and Venice.
His paintings also represent his gardens and interior of the his house in Gerberoy where he moved in 1901-1902 and where the human presence is indicated by a table or an open book, adding intimacy and mystery to his paintings.
From 1897 and till his death, he regularly exhibited in Paris, Londres, Brussels and in the USA. In 1930 he became professor at the Académie des Beaux-Arts and in 1937 became its president.