Howe Browne was the son and heir of John Browne, 1st Marquess of Sligo. He was educated at Eton and Jesus College, Cambridge, receiving his MA as Lord Altamont in 1808. He became Marquess of Sligo in 1809 on the death of his father and was appointed a Knight of the Order of St Patrick on 11 November 1809. On 4 March 1816 he married Hester Catherine, daughter of John de Burgh, 13th Earl of Clanricarde. In 1834-35 he was Governor and Vice-Admiral of Jamaica. He is remembered in Jamaica as a champion of slaves, and the first free village of Sligoville in Saint Catherine parish, Jamaica is named after him.
He is buried in Kensal Green Cemetery. The grave lies in the centre of the overgrown north-west quadrant of the inner circle.