Sharp was born in Bishop Auckland, the son of an insurance agent. He attended the grammar school in Bishop Auckland and left in 1918 to work with the borough surveyor for the next four years. He eventually worked as regional planning assistant to the South West Lancashire Regional Advisory Group, but after credit for his mammoth report was given, as was traditional, to the honorary surveyor, he angrily resigned, setting a precedent he was to follow more than once. For two years he was unable to find work.
Sharp used his leisure to write Town and Countryside (1932), an angry polemic which established him as an eloquent controversialist. He challenged the popular garden city movement, which sought to unite town and country, by insisting on their separate individual qualities. He finished the book in the family home in Durham, an area which provided the inspiration for much of his writing. He spent years as a consultant protecting Durham city from adverse development.
Sharp regarded the man-made English landscape as the most beautiful in the world and the English village as the perfection of the village idea. His thoughts on this, and on townscape, were expressed in English Panorama (1936), written after an unplanned move into Durham University's architectural department in Newcastle. Here also he edited the Faber Guide to Northumberland (1937) and produced his celebrated Town Planning (1940) a Pelican book which sold 250,000 copies. Sharp made a major contribution to the influential Scott report on land utilisation in rural areas which laid the foundations for post-war legislation to protect the countryside. He later wrote The Anatomy of the Village (1946), which became a classic on the subject of village design, despite being almost suppressed by the ministry. In it he developed his dramatic vision of townscape, then a largely unknown concept, and perfected it in his outstanding analyses of historic towns - notably Durham, Oxford, Exeter, Salisbury and Chichester.
Sharp's remaining years as a consultant based in Oxford were filled with frustration, as his own inability to compromise made employment hard to find, though he did work for the Forestry Commission in the North East; Stonehaugh, west of Wark on Tyne and Byrness village in upper Tynedale were designed by him in the early 1950s. Planning departments grew and consultants like Sharp were out of fashion. He expended his energy on poems and novels which remained largely unpublished. His last planning book was Town and Townscape (1968).