He served during the Battle of Buxar, and he was the highest commander of the Mughal army from 1772 till his death in April 1782.

[2][3] He was more successful than his predecessor Najib ad-Dawlah, the Rohilla Afghan appointed by Ahmad Shah Durrani to protect the Mughal throne.

[5][2] He started to suffer long bouts of fever and illness immediately after as he was appointed Vakil-i-Mutlaq or regent of Mughals in 1779 at the age of 42.

Nafaj spent much of his time drinking with this prostitute, until he fell seriously sick, feverish and weak to the extent "it could no longer be cured treated".

Inscription marked grave of Mirza Najaf Khan and his daughter, Fatima (died 1820 CE), are inside two marble cenotaphs.