He was born in Kazerun in October 1236 to a family with a tradition of Sufism. His father, Zia' al-Din Mas'ud Kazeruni was a physician and also a leading Sufi of the Kazeruni order. Zia' Al-Din received his Kherqa (Sufi robe) from Shahab al-Din Omar Suhrawardi. Qutb al-Din was garbed by the Kherqa (Sufi robe) as blessing by his father, aged ten. Later on, he also received his own robe from the hands of Najib al-Din Bozgush Shirazni, a famous Sufi of the time. Quṭb al-Din began studying medicine under his father. His father practiced and taught medicine at the Mozaffari hospital in Shiraz. After his father's death (when Qutb al-Din was 14), his uncle and other masters of the period trained him in medicine. He also studied the Qanun (the Canon) of the famous Persian scholar Avicenna and its commentaries. In particular he read the commentary of Fakhr al-Din Razi on the Canon of Medicine and Qutb al-Din raised many issues of his own. This led to his decision to write his own commentary, where he resolved many of the issues with Nasir al-Din al-Tusi.