Kubelík was born in Býchory, Bohemia, Austria-Hungary, today's Czech Republic, the day after Archduke Ferdinand's assassination that triggered the First World War. He was the sixth child of the Bohemian violinist Jan Kubelík, whom the younger Kubelík described as "a kind of god to me". His mother was a Hungarian countess, Anna Julie Marie Széll von Bessenyö. Kubelík studied the violin with his father, and entered the Prague Conservatory at the age of 14, studying violin, piano, composition, and conducting. He graduated from the conservatory in 1933, at the age of 19; at his graduation concert he played a Paganini concerto and a composition of his own for violin and orchestra. Kubelík was also an accomplished pianist, and served as his father's accompanist on a tour of the United States in 1935.