Gustavo Martz-Schmidt was a prominent artist of the "golden age" of Spanish humorous and satirical comics (1943-1961). He began drawing in his native Cartagena, but moved to Barcelona to start a professional career in comics. He created numerous memorable characters, such as 'Don Usurio', 'Don Prudencio', 'Don Danubio', 'Troglodito', 'El Doctor Cataplasma', 'El Sheriff Chiquito', and 'Polvorilla'.
These characters appeared in a variety of magazines, such as Pulgarcito, DDT, Zipy y Zape, Tio Vivo and Mortadelo. He also took over the 'Doña Urraca' series, twelve years after the death of Jorge, the creator of the series, in 1972.