Trained as a lithographer, in 1900 he settled in Paris to practice his trade. There he developed a passion for drawing, painting and engraving. Additionally, he began contributing to Jean Grave's Temps Nouveaux. Mobilized during World War I, he nevertheless contributed to Pierre Chardon's clandestine newspaper Semeur in 1916.
Portraits of famous anarchists, antimilitarist illustrations, naturist landscapes and various wood engravings by Moreau decorate many libertarian books and journals including Les Humbles, La Revue Anarchiste, l'Almanach de la paix (1934), L'Unique (until 1956) and numerous titles from Joseph Ishill's Oriole Press.
Although an artist of immense talent, Moreau rejected stardom and mocked official recognition. Manuel Devaldès, a friend and fellow artist, wrote his biography in 1935.