Beaufort was born in Navan in Ireland; his father was a cleric of Huguenot origin who took an active interest in geography and topography, publishing in 1792 one of the earliest detailed maps of Ireland. Beaufort joined the East India Company in 1789 and enlisted in the Royal Navy the following year, remaining on active service until 1812.

He proposed, in 1806, the wind scale named for him. This was an objective scale ranging from calm (0) up to storm (13) in which wind strength was correlated with the amount of sail a full-rigged ship would carry appropriate to the wind conditions. It was first used officially by Robert Fitzroy in 1831 and adopted by the British Admiralty in 1838. When sail gave way to steam the scale was modified by defining levels on it in terms of the state of the sea or, following George Simpson, wind speed.

In 1812 Beaufort surveyed and charted the Turkish coast, later writing his account of the expedition, Karamania (1817). He was appointed hydrographer to the Royal Navy in 1829. In this office Beaufort commissioned voyages to survey and chart areas of the world, such as those of the Beagle with Charles Darwin and the Erebus with Joseph Hooker. The sea north of Alaska was named for him.