Maskelyne, who was born in London, was educated at Westminster School and Cambridge University. He became the fifth Astronomer Royal in 1765 and, from 1782, rector of North Runcton in Norfolk.

Maskelyne spent considerable time trying to solve the problem of determining longitude at sea. His preferred method was by means of lunar observation, since, on a trip to St. Helena in 1761, he had successfully used such a method. To popularize his technique he published his British Mariner's Guide in 1763 and started publishing in 1767 the Nautical Almanac to provide the necessary information. He was a member of the Board of Longitude, which had been set up in 1714 to decide on the award of the £20,000 prize for a solution to the problem. Perhaps his commitment to his lunar method made him blind to the value of the chronometer invented by John Harrison, which he was asked to judge. He refused to recommend it for the award.