A son of Mas'ud III (r. 1099–1115), Shir-Zad served as a governor in India during his father's reign.
The deputy governor of Shir-Zad was Qiwam al-Mulk Nizam al-Din.
During his governorship, Shir-Zad became very close friends with the Persian poet Masud Sa'd Salman, who had recently been released from his imprisonment at Nay.
[2] It was probably at his accession that Shir-Zad adopted the laqab (honorific epithet) of Kamal al-Daula.
Shir-Zad fled to the Caspian lands, where he received shelter by the ispahbad (ruler) of the local Bavand dynasty of Tabaristan.