Hoppner was born in London to German parents who lived at the court of King George II. There were rumours that Hoppner was the illegitimate child of George III, but although Hoppner himself never denied this, there is no credible evidence to support these claims. He studied at the Royal Academy Schools from 1775 until 1781, the year in which he married Phoebe Wright. Throughout the 1780s his reputation as a portraitist advanced, until by the end of the decade he was widely regarded as a worthy successor to Reynolds and Gainsborough. The early 1800s brought considerable success for Hoppner, but his frail health was increasingly failing. He died in London aged only 51.