Samuel Whitbread was born at Cardington in Bedfordshire, the seventh of eight children. He left for London aged 14 and became an apprentice. He entered into partnership with Mr Shewell, and after the latter's death became sole proprietor in 1761. The brewery started at Chiswell Street in London.
Whitbread was elected Member of Parliament for Bedford in 1768, and held the seat until 1790. Said to have been the first to mention slavery in the House of Commons.
In May 1787 the brewery was visited by King George III and Queen Charlotte.
His son was the politician, Samuel Whitbread.