No biographical details are currently known, but, from the films he appeared in, it is safe to say that he was based in Barcelona.
He looks to be another actor who came to the profession quite late in life, at least as far as his known career is concerned. Initially at least he can't have been quite as old as he appears, given that he was playing lecherous old men with bad teeth in the early 60's and was still playing the same roles 20 years later.
Given that he has quite a few uncredited roles and that his filmography is quite sparse in places, then it would seem likely that there could be undocumented roles to be found.
- La vida es maravillosa .... Waiter at 'El Molino' (credited - uncertain identification)
1960 - Gaudí .... (credited, but not found)
1962 - Detective con faldas .... Monsieur Legrand (uncredited)
- Los culpables .... Forensics expert (credited)
1964 - A tiro limpio .... Office clerk at the Board of Trustees (uncredited)
- El mujeriego .... Old man (credited)
- Piso de soltero .... Federico (credited)
1965 - El castigador .... Wedding guest (credited)
- L'uomo che viene da Canyon City .... Telegraph operator (uncredited)
- La chica del autostop .... Don Matías (uncredited)
- La dama de Beirut .... Waiter (uncredited)
- Muere una mujer .... Choreographer (uncredited)
- Pistoleros de Arizona .... Pianist (uncredited)
1968 - El Baldiri de la costa .... Quim (credited)
- La viudita ye-yé .... Priest (credited)
1969 - El señorito y las seductoras .... Friar (credited)
- Españolear .... Remigio (credited)
1970 - La banda de los tres crisantemos .... Telegraph office employee (credited)
- Percy Stuart (TV series) S. 3, ep. 7: "Der Koffer" .... Pedro (credited)
1971 - Abre tu fosa amigo... llega Sábata .... Telegraph operator (credited)
- Topical Spanish .... Old man in a hurry (credited)
1972 - El triangulito .... Man waiting for the display to start (uncredited)
- Los fabulosos de Trinidad .... Jiménez's secretary (credited)
1973 - Aborto criminal .... Waiter (credited)
- Busco tonta para fin de semana .... Rodríguez (credited)
- Ninguno de los tres se llamaba Trinidad .... Stagecoach passenger (credited)
- Samrtno prolece .... Party guest (uncredited)
1974 - Antonio Gaudí, una visión inacabada .... Priest (credited)
1975 - Furia española .... Priest (credited)
1976 - El jovencito Drácula .... Hawkins (credited)
- Hic Digitur Dei .... Old man in the wheelchair (credit unknown)
- La nueva Marilyn .... Bubby (credited)
- Libertad provisional .... Catalan grandfather (uncredited)
1977 - Fraude matrimonial .... Art critic (credited)
- La viuda andaluza .... role unknown (credited)
- Las alegres chicas de 'El Molino' .... El Molino audience member (credited)
- Las marginadas .... Fermin (credited)
1978 - Los violadores del amanecer .... Man accompanying the girls at the line-up (uncredited)
- Vámonos, Bárbara .... Ana's uncle (uncredited)
1979 - Companys, procés a Catalunya .... Senyor Cua (uncredited)
- La basura está en el ático .... Doctor Nogueri (uncredited)
1980 - La amante ingenua .... Company director (credited)
1981 - Dos pillos y pico .... Nati's grandfather (uncredited)
- Elisabet (1968) IMDb
- Amor y medias (1969) IMDb
- Los caballeros de 'La antorcha' (1969) IMDb
- Farsa italiana de la enamorada del rey (1976 TV movie) IMDb as Duke of Nebreda
- Cuarenta años sin sexo (1979) IMDb as Agapito's father
- La plaça del Diamant (1982) IMDb as Old man from the postcard. The credit here is for "Joan Fernández". I checked the episode and did not find Juan, though if he only appears in an image on a postcard then I guess I could have missed him.