Wilson entered the House of Commons as Liberal Member of Parliament for Westbury, Wiltshire, in 1847. Because of his economic experience, in 1848 prime minister Lord John Russell appointed Wilson as Secretary of the Board of Control, which supervised the East India Company’s control of British India, a post he held until the government fell in 1852. He then served as Financial Secretary to the Treasury between 1853 and 1858, firstly in Lord Aberdeen's coalition government and secondly in Lord Palmerston's first administration. In 1857 he was returned to Parliament for Devonport. He again briefly held office under Palmerston as Paymaster-General and Vice-President of the Board of Trade between June and August 1859 and was sworn of the Privy Council the same year.