 In 1653 he married Katharine, only daughter and heiress of James Smith of Tillington, by whom he had an only son, James, who died in 1691 before his father.It was not until 1677 that William gained prominence, being elected a Serjeant-at-law.In March 1677 the election of Sir Thomas Williams as a Member of Parliament for Weobly was called into question and declared void, so William Gregory offered himself as a candidate and was elected without opposition on 9 March.