His father was Alfonso Gumucio Reyes, a leader of the Movimiento Nacionalista Revolucionario (MNR), Minister of Economy during the Government of Víctor Paz Estenssoro, and Ambassador to Uruguay and Spain.

Back in Bolivia in 1978 he directed a number of documentaries on cultural and social issues, as he worked at the Centro de Investigacion y Promocion del Campesinado (CIPCA), a Bolivian NGO, and published as a journalist in various daily newspapers and weekly journals.

His short stories, poems and essays have been selected in about 30 anthologies and collections, among them those edited by John Downing, Julianne Burton, Manuel Vargas, Raquel Montenegro, Cecilia Pisos, Víctor Montoya, Rosario Santos, Jan Servaes, Bruce Girard, Paulo Antonio Paranagua, Ángel Flores, Tim Barnard, Sandra Reyes, and Alan O'Connor.

Gumucio Dagron studied film in France and worked as assistant director to Alan Labrousse and Jorge Sanjines, and as a scriptwriter for Antonio Eguino.

Dagron's documentary film Bolivia: Union Rights (1988), part of the People Matter series produced by AVISE, was aired by the Dutch television.

Over the years, his photographic work has been shown in personal and collective exhibits on Bolivian landscapes and people (Altiplano, 1989) and portraits of artists from Latin America (Retrato Hablado, 1990).

Books such as Realizando el Futuro published by the Corporación Andina de Fomento (CAF), Ciudad de La Paz, Luz, Magia y Tradición published by the Municipality of La Paz, included his photographs, as well as Imágenes del Trabajo, awarded at the 4th International Art Contest organized by the International Labour Organization (ILO) in 1986.