From 1887 he figured among the exhibitors of the Salon, where he showed numerous portraits and genre pictures, but his popular fame is due to his comic drawings and caricatures. The series of the "Gotha des souverains," published in Le Rire, and Leandre"s other work like that seen in L"Assiette au Beurre placed him in the front rank of modern caricaturists. Besides his contributions to Le Rire, Le Figaro and other comic journals, he published a series of albums: Nocturnes, Le Musee des souverains, and Paris el la provénce.
In 1904, he created the Société des Peintres Humoristes.
Léandre produced admirable work in lithography, and designed many memorable posters, such as the "Yvette Guilbert." "Les nouveaux maries," "Joseph Prudhomme," "Les Lutteurs," and "Louisiana Femme au chien."
He died in 1934 in his Caulaincourt street studio, in Montmartre.