De la Iglesia was an outspoken gay and socialist filmmaker who is relatively unknown outside Spain despite a prolific and successful career in his native country.

He attended courses at the prestigious Parisian Institut des hautes études cinématographiques, but he could not enter Spain's national film school because he wasn't yet 21, the minimum age required for admission.

De la Iglesia made his debut as film director when he was age 22 with Fantasia 3 (Fantasy 3, 1966), adapting three children's stories: The Maid of the Sea, The three hairs from the devil and The Wizard of Oz.

[1] His films did not attract widespread notice until his fourth effort, the critically acclaimed thriller El Techo de Cristal (The Glass Ceiling, 1970).

[1] During the early 1970s, de la Iglesia was a member of the Spanish Communist Party; his films of this period reflected his beliefs and often centered on violent forms of social protest.

He approached the horror genre in his two following films: La semana del asesino (The Cannibal Man, 1971) and Nadie oyó gritar (No One Heard the Scream, 1972), leaving stylistic and structural academicism aside.

His film Una gota de sangre para seguir amando (Murder in a Blue World, 1973), written with José Luis Garci, a mixed of futuristic thriller, took some cues from Stanley Kubrick's A Clockwork Orange.

Claiming that his addiction to cinema was stronger than his drug problems, de la Iglesia eventually kicked his habit and resumed his career making Los novios bulgaros (The Bulgarian Lovers, 2003), a film based on the novel of the same title written by Eduardo Mendicutti.