His sister Anne married Sir Samuel Dashwood, MP and Lord Mayor of London.

He matriculated at St John's College, Oxford, on 18 May 1672, aged 16, and was admitted at the Middle Temple in 1674.

He was returned unopposed for Andover at the 1705 general election and was chosen as Speaker of the House of Commons in 1705.

He was proposed for this position by his joint partner in the Company of Scotland, Francis Montgomerie of Giffen.

[3] At the 1708 general election Smith was returned unopposed as MP for Andover, and subsequently gave up his position as Speaker when he was appointed Chancellor of the Exchequer again on 22 April 1708.

He ceased to be Chancellor at the dissolution of Parliament on 11 August 1710, and was returned unopposed for Andover at the 1710 election.