Scottish naval surgeon and naturalist who made accurate surveys of more of the Canadian Arctic coast than any other explorer.

After receiving his medical qualification at the University of Edinburgh and passing the examination of the Royal College of Surgeons of London (1807), Richardson was commissioned in the Royal Navy, in which he served for 48 years, rising from assistant surgeon to inspector of hospitals and fleets. Between 1807 and 1814 he was assigned to five ships in succession, seeing action at Copenhagen, at the blockade of the Tagus River, in convoys to Spain and Quebec, at Madeira, and finally in the Baltic fleet.

Between 1819 and 1822 Richardson was surgeon and naturalist in Sir John Franklin's (Franklin, Sir John) first overland expedition to the Canadian Arctic coast. From 1824 to 1827 he was surgeon and naturalist and second in command of Franklin's second overland expedition, in the course of which Richardson surveyed some 900 miles (1,449 km) of Canadian Arctic coast between the Mackenzie and Coppermine rivers. He was knighted in 1846. In 1848–49 Richardson, with John Rae as second in command, made an overland journey in search of Franklin's lost third Arctic expedition that had started in 1845. They explored the region between the estuary of the Mackenzie River and Cape Kendall in the Union and Dolphin straits but were unable to find any trace of Franklin's ships.

Richardson was also a prolific and important writer in several fields in natural history, especially Arctic biology and general ichthyology.