He was the third child (out of four) of Adriaan Victor Janssen (1854–1942) and Anna Catharina Eelen (1855–1929). He went to high school in Hoogstraten and studied medicine at the Catholic University of Leuven and the University of Ghent.
He was the third offspring (out of four) of Adriaan Victor Janssen (1854–1942) and Anna Catharina Eelen (1855–1929). He attended high school in Hoogstraten and pursued a degree in medicine at the Catholic University of Leuven and the University of Ghent.