Mir Jafar or Sayyid Mir Muhammed Jafar Ali Khan bears the formal title of Shuja ul-Mulk, Hashim ud-Daula, Nawab Jaafar Ali Khan Bahadur, Mahabat Jang. The common name of the Nawab is Mir Jafar. He was the second son of Sayyid Ahmad Najafi and was Nawab of Bihar, Bengal and Orissa. He is commonly remembered in India by the name of Gaddar-e-Hind (whose English translation is `The Traitor of India`). Mir Jafar took over the reign as the eighth Nawab of Bengal from Siraj-Ud-Daulah and also counted as the first of Najafi dynasty.

Mir Jafar became the Nawab of Bengal after cheating Nawab Siraj-Ud-Daulah and surrendering the Nawab`s army against Robert Clive in the battle field. The rule of Mir Jafar is largely regarded as the initiation of the rule of British in India. It was thus a key stem in the complete domination of British in India. A Punjabi by origin, Mir Jafar visited Bengal as a bankrupt adventurer. He got a job in the army of the Nawab and gradually promoted himself. Nawab Alivardi Khan afterwards married off his half-sister Shah Khanam and provided 7000 horses to command. His early military career was glorious. Mir Jafar rescued the nephew of Alivardi Khan, the hapless Sauqat Jung, from the hold of Mirza Baqir at Katak. He also played a vital role in various military campaigns of Alivardi Khan, particularly against the Marathas and against the earlier Nawab Murshid Quli Khan`s grandson.

Mir Jafar was a man of high ambitions. Proud of being in the position which he was given, Mir Jafar stole the opportunity of setting a conspiracy along with Ataullah (the faujdar of Rajmahal) of murdering Alivardi Khan, who was destabilized by a series of struggle with the Marathas. But the conspiracy was disclosed and Mir Jafar was deprived of most of his powers. Then he returned to Murshidabad and was successful to win the trust of Siraj-Ud-Daulah, the grandson of the Nawab, and gradually reassured his prominence and power. There he also conspired with Shawkat Jang to invade Bengal, which got disclosed before Siraj and he replaced him with Mir Madan in the position of the Bakshi. In the year 1756, Siraj won from the British, the Cossimbajar factory and then proceeded towards Kolkata (Calcutta) but the British quickly struck back and Siraj was forced to escape to Murshidabad. He asked for help from Mir Jafar who had assured him to help against the British. But, in reality, there was a pact between the British and Mir Jafar to overthrow Siraj and to make him the Nawab of Bengal.

The British soldiers under the command of Robert Clive advanced to Murshidabad and confronted Siraj in the Battle of Plassey in the year 1757. The army of Mir Jafar betrayed Siraj-Ud-Daulah by denying fighting for him and in the end the Nawab, Siraj was defeated and killed. Mir was made the new Nawab of Bengal, Bihar and Orissa. Mir Jafar was thus Bengal`s first Nawab under the influence of British. However, Mir Jafar realised that the expectations of the British were boundless and attempted to set free from them with some assistance from the Dutch. The Dutch were defeated by the British in the Battle of Chinsurah in the month of November 1759 and retaliated by compelling Mir to renounce the throne in favour of Mir Qasim, his son-in-law. Mir Qasim turned out to be an able and independent ruler who desired to live without bowing down to the British. The Company very soon fought with him, and Mir Qasim was finally overthrown. Mir Jafar however was able to gain the confidence of the British and he was again made the Nawab of Bengal in the year 1763, and was there till he died in the year 1765.