Wulff was born in Osnabrück and is Roman Catholic. His father left the family, and he grew up with his mother. As a teenager, he had to take responsibility for the care of his younger sister, after his mother developed multiple sclerosis. After completing his Abitur at the Gymnasium in Osnabrück, Wulff went to study law. He specialised in economic law at the University of Osnabrück. In 1987 and 1990, he passed the first and second state examinations in law. He started to work as a lawyer.