In 1739, he succeeded his father-in-law and maternal uncle, Burhan-ul-Mulk Saadat Ali Khan I to the throne of Awadh/Oudh and ruled from 19 March 1739 to 5 October 1754.

When Ahmad Shah Bahadur ascended the throne at Delhi in 1748, Safdar Jang became his Wazir-ul-Malik-i-Hindustan or Prime Minister of Hindustan.

Balaji Baji Rao dispatched Scindia and Holkar chiefs to prevent Nasir Jung's forces from reaching Delhi, and thus, saved Safdar Jang.

[1] Safdar Jang had maintained a contingent of 20,000 "Mughaliya" cavalry, most of whom were Hindustani Muslims, many who were chiefly from the Jadibal district of Srinagar in Kashmir, who had imitated the Qizilbash in dress and spoke the Persian language.

[3][4] The state also saw a large migration of Kashmiri Shi'as to the Shi'a kingdom of Awadh, both to escape persecution and to secure courtly patronage.