Initially, he became superintendent over its trade in Bengal. Then, in 1787, having first acquired a personal fortune through silk manufacturing in Malda, Lord Cornwallis the Governor-General appointed Grant as a member of the East India Company's board of trade.
Grant began by controlling the commercial activities in Bengal. Subsequently, in 1787, having built up his personal fortune through silk manufacturing in Malda, Lord Cornwallis, as the Governor-General, chose Grant to be part of the East India Company's trade council.