Hossein Beg Laleh Shamlu was a Qizilbash officer of Turkoman origin, who occupied high offices under the Safavid king Ismail I (r. 1501-1524) and was the first person to serve as the vakil (vicegerent) of the empire.
Hossein belonged to the Shamlu tribe, one of the seven Turkoman tribes of the Qizilbash, a Shia militant group, which supported the young Safaviyya leader Ismail I, who had taken refuge in Gilan to avoid the Aq Qoyunlu, a Turkic tribal federation which controlled most of Iran. During Ismail's stay in Gilan, Hossein Beg served as his guardian and mentor. In 1500, Ismail came out of hiding and with the aid of the Qizilbash, invaded Shirvan, killing its ruler Farrukh Yassar. In 1501, all of Shirvan, Arran and Azerbaijan was under the control of Ismail, who laid foundation to the Safavid dynasty.
He then appointed Hossein Beg as the vakil of the empire and the commander-in-chief (amir al-umara) of the Qizilbash army. By 1504, all of present-day Iran was under the control of Ismail. In 1507, Hossein Beg campaigned in western Iran, where he was ambushed by a group of Kurds and as a result lost 300 men. During the same year, Ismail appointed the Iranian Mir Najm Zargar Gilani as the new vakil. This was because Ismail favored the Iranians more than the Qizilbash, who although had played a crucial role in Ismail's campaigns, possessed too much power and were no longer very trustworthy. One year later, an Safavid army under Hossein Beg and Ismail captured Baghdad. In 1509/10, Hossein Beg lost his office as commander-in-chief in favor to a man of humble origins, Muhammad Beg Ustajlu. In 1512, Hossein Beg, along with the rest of the Qizilbash commanders, betrayed the Safavid vakil Najm-e Sani and left him to die at the Battle of Ghazdewan.