Společně s Buenaventurou Durrutim a Franciscem Ascasem založil Los Solidarios, anarchistickou skupinu, která například provedla neúspěšný atentát na španělského krále Alfonsa XIII.
Santa Cruz first wrote the script for a film, Un Señor mucamo, in 1940 but it was not until ten years later in 1950 that his career had a breakthrough with his adaptation of the 1895 Oscar Wilde play, The Importance of Being Earnest in Al…