[1] Born in Santiago, he was the second son of Ramón Subercaseaux Vicuña, a career diplomat, Ambassador of Chile to the Holy See for more than two decades, and Amalia Errázuriz Urmeneta, writer and author of the book "Rome of the spirit".

According to the Comité Olímpico de Chile, Luis Subercaseaux Errázuriz competed at the age of 13 in the 100, 400 and 800 metres.

[5] An appraisal of a famous photo of series 2 of the 100 meters sprint, performed by facial recognition experts of the Chilean forensic police, concluded that Subercaseaux was one of the participants.

[6] During this period in his life, he studied at the Colegio Benedictino located in the Basque Provinces of France, where he kept his record on the high jump.

[citation needed] Through 1928 he was ambassador of Chile in Peru, Spain and the Vatican, in addition to being an attendant of Chilean business in Belgium, Czechoslovakia, Greece, the Netherlands, Norway, Poland and Yugoslavia from the consular office in London.