He was born in Santiago on 14 December 1892, the son of Juan Benaprés and Elena Lafourcade.[1] He married Jesús Arrau Ugarte, with whom he had six children.[1]
He studied in Europe and later attended the Chilean Military Academy (Escuela Militar de Chile).[1] Over a military career spanning 28 years, he rose to the rank of colonel before retiring in 1932.[1] During his service, he held positions as Staff Officer, Professor at the War Academy, Deputy Director of the Military School, and Delegate of the Army General Staff to the Navy’s General Directorate.[1]
After retiring, Benaprés joined the Agrarian Labor Party and was elected Deputy for the 6th Departmental Group (Valparaíso and Quillota) for the 1953–1957 term.[1] He served on the Standing Committee on National Defense.[1]
Benaprés was also the owner of «La Bandera» publishing house and the author of the textbook Libro de Lectura para el Ejército (“Reading Book for the Army”).[1] He was a member of several cultural and social organizations, including Santiago Atlético, the Mutual Protection Society of Chile, the French Circle, and was an honorary member of Stade Français.[1] He was also an honorary member of the Military Club, the Circle of Retired Officers, and the Automobile Club.[1]
For his military service, he received the Medal for 20 Years of Service in the Chilean Army and the Centennial Medals of Argentina and Chile.[1]
He died in Santiago on 27 October 1955 while serving as Deputy; he was replaced by Augusto Pumarino Fuentes, who assumed office on 21 May 1956.[1]