A firmly Whig politician, Earl Grey oversaw four years of political reform that had enormous impact on the development of democracy in Britain. He first took office briefly under Grenville in 1806, but it was nearly a quarter of a century before he returned to office as PM. Earl Grey's most remarkable achievement was the Reform Act of 1832, which set in train a gradual process of electoral change. Indeed, it sowed the seeds of the system we recognise today. Around 130 years of parliamentary reform began with this act and culminated in universal suffrage for men and women over 18, secret ballots and legitimate constituencies.

The battle to pass the historic act was a difficult one. Grey resigned after the Lords rejected it, although he returned to office when Wellington found himself unable to form an administration. Wellington then consented, and Grey was able to push the bill through. Other reforming measures included restrictions on the employment of children, and the abolition of slavery in the British Empire in 1833.

One of Grey's other legacies is the blend of tea known as Earl Grey. He reputedly received a gift, probably a diplomatic present, of tea that was flavored with bergamot oil.