Hubert Pierlot was educated in religious schools in Maredsous and later attended the prestigious Jesuit "Collège Saint-Michel" secondary school in Brussels. He studied at the Catholic University of Louvain where he received a "licence" in Political Science and a doctorate in Law. During his early life, he travelled to the United States, Canada and the United Kingdom. He later married Marie-Louise ( De Kinder) and had seven children. With the German invasion of Belgium in August 1914, he volunteered for the Belgian infantry as a private. He served at the Battle of the Yser and on the Yser Front where he was decorated for valour. By the end of the war, he had reached the rank of Lieutenant and was serving in the 20th Regiment of the Line.