Between 1 April 1917 and 1920 he was in the fighting zone in World War I where he worked in the field hospitals. He first served as a sergeant and later went into training as an officer in the medical corps. He resumed his studies in 1920 after being discharged that April. On 6 July 1921 he graduated at the top of his class in surgical and medical studies. From 1921 to 1924 he spent time in doing practical experience with his doctor uncle and after this for a short time served for a brief period as an assistant in the medical practice at Vernate before being appointed to the practice of Morimondo in Milan. In 1922 he passed his internship with high honours at the Milano Instituto di Ostetricia e Ginecologia.