Cartier first arrived in India as a writer in the service of the British East India Company. He was expelled from Dacca in 1756 while serving there as an assistant. After fleeing with other fugitives to Fulta, he joined Clive of India and helped in the retaking of Bengal, for which he was praised by the Court of Directors of the British East India Company. Cartier's career accelerated after the Battle of Plassey. In 1761 Cartier became chief of the Dacca factory. By 1767 he was Second in the Calcutta Council.

On December 26, 1769 Cartier succeeded Harry Verelst as Governor of Bengal. Cartier was governor at time of the Bengal famine of 1770, during which one-third of the populace died. Cartier was blamed for ignoring warnings about the impending disaster but was able to use a magazine of grain to feed fifteen thousand people every day for some months. In response to the crisis, the Court of Directors sent a three-person commission to Bengal to assess the situation. En route, however, the ship carrying the three members foundered at sea. The Court of Directors did not send a replacement and recalled Cartier. Warren Hastings was selected as his replacement; he took office on April 13, 1772.

Cartier became a High Sheriff of Kent in 1789. Unusually the previous encumbent, James Bond, continued from the year before and Cartier served only for the latter part of the year.

Cartier died in Bedgbury, Kent on January 25, 1802. He was eulogized by Edmund Burke for his government of Bengal. His wife, Stephana, survived him and died aged 80 also in Bedgbury on 22 August 1825.He was also recognized as one of the best explorer's in the world! Plus he took native americans as slaves