Nadir Khan had served in Amir Habibullah's royal bodyguard, and eventually rose to be commander-in-chief of the army. When Habibullah was assassinated, Nadir Khan continued to serve Aminullah for some years, but he was living in virtual exile in France when the news of Kabul's capture by Bacha-i-Saqao reached him. Nadir Khan immediately sailed for India. Without funds, and at first without either foreign or tribal support, he and his brothers journeyed to the Khost frontier to rally the tribes. He finally won enough support among tribesman on the Indian side of the frontier to defeat Bacha-i-Saqao and seize Kabul. An assembly of tribal chiefs proclaimed him "King of All Afghans".
Nadir Shah set up a new administration based on orthodox Islamic law and outlined plans to develop his country. During his brief reign internal revenue was raised, a 40,000-man army created, a road built through the Hindu Kush, and the highways of the country made safer than they had ever been before.
In spite of the king's vigilant efforts to root out opposition, the son of a servant of an executed conspirator shot King Nadir Shah at a school-prize competition in 1933. For once family solidarity overrode personal ambition in Afghanistan, and the Mosahiban brothers took immediate steps to ensure the accession of his son to the throne, King Zahir Shah.