Mott was appointed a Lecturer in the Physics Department at the University of Manchester in 1929. He returned to Cambridge in 1930 as a Fellow and lecturer of Gonville and Caius College, and in 1933 moved to the University of Bristol as Melville Wills Professor in Theoretical Physics.

But already in the middle of the 1930s, Mott's interests had broadened to include solid states, leading to two more books that would have a great impact on the development of the field in the years prior and after World War II. In 1936, Theory of the Properties of Metals and Alloys (written together with H. Jones) describes a simplified framework which led to rapid progresses.

Mott was elected a Fellow of the Royal Society (FRS) in 1936. Mott served as President of the Physical Society in 1957. In the early 1960s he was chairman of the British Pugwash group. He was knighted in 1962.

The concept of nearly free valence electrons in metallic alloys explained the special stability of the Hume-Rothery phases if the Fermi sphere of the sp Valence electron, treated as free, would be scattered by the Brillouin zone boundaries of the atomic structure. The description of the impurities in metals by the Thomas Fermi approximation would explain why such impurities would not interact at long range. Finally the delocalisation of the valence d electrons in transitional metals and alloys would explain the possibility for the magnetic moments of atoms to be expressed as fractions of Bohr magnetons, leading to ferro or antiferromagnetic coupling at short range. This last contribution, produced at the first international conference on magnetism, held in Strasbourg in May 1939, reinforced similar points of view defended at the time in France by the Future Nobel laureate Louis Néel. In 1949, Mott suggested to Jacques Friedel to use the approach developed together with Marvey for a more accurate description of the electric-field screening of the impurity in a metal, leading to the characteristic long range charge oscillations. Friedel also used the concept developed in that book of virtual bound level to describe a situation when the atomic potential considered is not quite strong enough to create a (real) bound level of symmetry e ≠ o. The consequences of these remarks on the more exact approaches of cohesion in rp as well as d metals were mostly developed by his students in Orsay.

When Mott returned to Bristol after the war, (during that period, he worked on the role of plastic deformation on the progression of fracture cracks), his having met and hired of Frederick Charles Frank led both of them to develop, with the help of others such as Frank Nabarro and Alan Cottrell, to attack with the field of dislocations, in which Bristol shone with a new vigor, especially at the end of the 1940s. If Mott only produced early and somewhat minor contributions to that field, notably on alloy hardening with Nabarro and on the topology of a dislocation network lowering the apparent elastic constants of a crystal, there is no doubt that Mott's enthusiasm played its role in the three major steps forward in the field by F. C. Frank on crystal growth and plasticity and later, in Cambridge, by P. Hirsch on the thin film electron microscopy.

In 1948 he became Henry Overton Wills Professor of Physics and Director of the Henry Herbert Wills Physical Laboratory at Bristol. In 1954 he was appointed Cavendish Professor of Physics at Cambridge, a post he held until 1971. He was instrumental in the painful cancellation of the planned particle accelerator because of its very high cost. He also served as Master of Gonville and Caius College, 1959–1966.

Mott received an honorary Doctorate from Heriot-Watt University in 1972.

In 1977, Nevill Mott was awarded the Nobel Prize in Physics, together with Philip Warren Anderson and John Hasbrouck Van Vleck "for their fundamental theoretical investigations of the electronic structure of magnetic and disordered systems." The news of having won the Nobel Prize received Mott while having lunch at restaurant Die Sonne in Marburg, Germany, during a visit to fellow solid state scientist at Marburg University.

In 1981, Mott became a founding member of the World Cultural Council.

Mott was married to Ruth Eleanor Horder, and had two daughters, Elizabeth and Alice. He died in Milton Keynes, Buckinghamshire. His autobiography, A Life in Science, was published in 1986 by Taylor & Francis.

In 1995, Mott visited the Loughborough University Department of Physics and presented a lecture entitled "65 Years in Physics". The University continues to host the annual Sir Nevill Mott Lecture.

His early works were on the theoretical analysis of collisions in gases, notably the collision with spin flip of an electron against a hydrogen atom, which would stimulate subsequent works by André Blandin and Jun Kondo about similar effects between conduction electrons, as well as magnetic properties in metals. This sort of activity led Mott to writing two books. The first one, which was edited together with Ian Sneddon, gives a simple and clear description of quantum mechanics, with an emphasis on the Schrödinger equation in real space. The second describes atomic and electronic collisions in gases, using the rotational symmetry of electronic states in the Hartree–Fock method.

N. F. Mott revived the old Philosophical Magazine and transformed it into a lively publication essentially centred on the then-new field of solid state physics, attracting Writers, readers and general interest on a wide scale. After receiving a paper on point defects in crystals by Frederick Seitz that was obviously too long for Phil. Mag, Mott decided to create a new publication, Advances in Physics for such review papers. Both publications are still active in 2017.