He held numerous posts in the government of the United Kingdom, namely Chancellor of the Exchequer, Leader of the House of Commons, Cofferer of the Household and First Lord of Trade.

Initially a supporter of Robert Walpole's government, in 1725 Sandys and his uncle Sir John Rushout went into opposition with William Pulteney.

Pulteney (created Earl of Bath that year) brokered a deal with the Court, without consulting opposition parties.

They opposed the repeal of the Septennial Act 1716, and objected to the rejection by the Lords of the Indemnification Bill to recompense witnesses against Walpole.

[2] On 9 June 1725 Sandys married Letitia, eldest daughter and co-heiress of Sir Thomas Tipping Bt MP and his wife Anne Cheke.