In 1774 he went into politics and was briefly elected to Parliament as the member for
Hindon, Wiltshire, by spending 15 guineas per vote. On petition the election was declared void due to bribery by the winning candidates. He and his fellow candidate,
Thomas Brand Hollis, were prosecuted, fined one thousand
marks, and imprisoned for six months. In a rerun of the election Brand Hollis withdrew his name but Smith was re-elected. He later served as MP for
Wendover in 1780 and as MP for
Wareham in 1790. and may have served as a "type" for
Samuel Foote's 1772 play of that title. He was satirically attacked by a Captain Joseph Price and a portrait of him appeared opposite that of
Elizabeth Armistead (one of the favourite courtesans, and eventually the wife, of
Charles James Fox) in
Town and Country Magazine. He gambled huge amounts, on horses and at cards, and is said to have lost heavily to Fox. ==Family and descendants==