After the elimination of Muhammad Aytimur, Shams al-Din 'Ali decided not to formally take over the Sarbadar government; he no doubt realized that a counter-coup was probable and that he would not have enough support amongst the partisans of Wajih ad-Din Mas'ud and the army to maintain his position.
Despite Kulu Isfandiyar's military credentials, he proved unsuitable as a ruler and was forcibly removed from power after only a year by supporters of Mas'ud's brother, Shams al-Din ibn Fazl Allah.
In order to avoid his predecessors' failure to pay the military, he increased the revenues of the state and made sure that officials and members of the army were paid in cash.
Corruption by government officials was heavily suppressed, which helped increase the state finances and fund both the army and several public works programs.
His reign came to a sudden end when a government official, Haidar Qassāb, organized his murder after being punished for allowing a tax account to fall into arrears.