Born and died in Khorasan, he studied in Damascus, went on a pilgrimage to Mecca and lived for a time in Tabrīz and Mosul.
Jāmī believed it was mysticism, but al-Dhahabī calls Ṣadr al-Dīn a Shāfiʿī jurist.
Saʿd al-Dīn appears to have returned to his uncle (then in Mosul) shortly before the latter's death in 1220.
[4] How long Saʿd al-Dīn remained in Jabal Qāsiyūn is unknown, but he eventually moved back to Baḥrābād, where he resided in his family's khānqāh (Ṣūfī school).
According to Ibn al-Karbalāʾī, shortly before his arrival in Tabrīz, he developed a disease which caused him to lose a finger.
According to a legend associated with this stay says that he saw the young Najm al-Dīn Zarkub Tabrīzī playing with other children in the street, placed his hand on his head and predicted his future greatness.
Ibn al-Karbalāʾī in his Rawḍāt al-jinān (1567) records instances of Saʿd al-Dīn predicting the future.
[3] The cause of his death is unknown; possibly it was related to the disease he had contracted almost two decades earlier.
His works can be roughly divided between those that are esoteric, which often contain ʿilm al-ḥurūf (letter and number mysticism), and those that are exhortative in a typically Kubrawī style.