He was a disciple of Imam Abu Hanifa. He along with Muhammad Shibani compiled the Fiqah-E-Hanfi that is followed almost all over the World. He was the author of Kitab-ul-Kharaj amongst others. In the history of Islam, he was the first person to be appointed as Qazi-ul-Quzat. His full name was Abu Yusuf Yaqub bin Ibrahim.