Born in Leeds, Mott studied at Cambridge University, gaining his bachelor's degree in 1927 and his master's in 1930. He never pursued a doctorate, but from 1930 until 1933 was a lecturer and fellow of Gonville and Caius College, Cambridge. Subsequently he moved to Bristol University as a professor of theoretical physics. In 1948 he became director of Bristol's physics laboratories, but returned later to Cambridge as Cavendish Professor of Experimental Physics, where he served from 1954 until his retirement in 1971.

Mott's work in the early 1930s was on the quantum theory of atomic collisions and scattering. With Harrie Massey he wrote the first of several classic texts, The Theory of Atomic Collisions (1934). Other influential texts that followed were on The Theory of Properties of Metals and Alloys with H. Jones (1936) and Electronic Processes in Ionic Crystals with R. W. Gurney(1940). Each marked a significant phase of active research. Mott began to explore also the defects and surface phenomena involved in the photographic process (explaining latent-image formation), and did significant work on dislocations, defects, and the strength of crystals.

By the mid 1950s, Mott was able to turn his attention to problems of disordered materials, liquid metals, impurity bands in semiconductors, and the glassy semiconductors. His models of the solid state became more and more complex, and included an analysis of electronic processes in metal–insulator transitions, often called Mott transitions.

In 1977 Mott shared the Nobel Prize for physics with Philip Anderson and John Van Vleck for their “fundamental theoretical investigations of the electronic structure of magnetic and disordered systems.” Mott was knighted in 1962. His autobiography, A Life in Science, was published in 1986.