Interested in art since he was a child, Comerio learned the basics of photography in the studio of the painter-photographer Belisario Croci. He then opened in own studio in 1894. His first work, a portrait taken secretly of King Umberto I during his trip to Como, bears the mark of his future work, aimed at documenting current events and pioneering photojournalism. Motivated by his own interest in spreading information through photography, Comerio also became a filmmaker. After becoming the photographer of the Royal House, he expanded his filmmaking career with very complex projects at a great cost. When the war ended, the dire financial situation forced him to end his film career, and after 1920 he also stopped taking photographs.