A their English author and historian, he is best known for his non-fiction work about Adolf Hitler and the Nazi regime. His best-known works include Hitler: A Profile in Power (1991) and Popular Opinion and Political Dissent in the Third Reich (1983).
He received degrees from the University of Liverpool and Merton College, Oxford. Later, he taught at the University of Sheffield in South Yorkshire, England.
He worked as a historical adviser for the BBC's documentary about the Third Reich.
He was born to Joseph Kershaw and Alice Robinson and was raised in the Roman Catholic faith in Lancashire, England. He married Betty Kershaw, who served as Dean at the University of Sheffield.
He was a key contributor to the 2001 BBC documentary, War of the Century, which focused on Adolf Hitler during World War II.