Rawlinson became a chancery lawyer. In Easter term 1686 he became a serjeant-at-law, and in 1688 at the revolution he was appointed one of the three Commissioners for the Great Seal. He helped to draft the amendments to the act which authorised the commissioners to execute the office of Lord Chancellor in March 1689 He was knighted by King William III at Hampton Court on 5 March 1689. In November 1690 he gave evidence before the House of Lords against the bill to reform the abuses of the court of chancery, and was allowed a chair in view of his infirmities. Rawlinson acted as commissioner of the seal for three years, but in March 1693 Sir John Somers became sole keeper. Somers also opposed the king's proposal to appoint Rawlinson chief Baron of the Exchequer to replace Sir Robert Atkyns, arguing that he was ignorant of common law.