He was born in Saint-Lô, France.
His most famous achievement is the discovery of Neptune, using only mathematics and astronomical observations. The calculations were made to explain discrepancies between Uranus's observed orbit and that predicted from the laws of Kepler and Newton. At the same time, but unknown to each other, the same calculations were made by Adams. Le Verrier assisted Galle in locating the planet (September - 1846); which was found within 1° of its predicted location at a point in Aquarius.
Perhaps galvanized by his discovery, Le Verrier proceeded to intepret the orbit of Mercury as influenced by another planet (tentatively named Vulcan). This triggered a wave of false detections, which lasted until 1915, when Einstein explained the anomalous motion with his theory of general relativity.