Salam, who was born at Jhang in Pakistan, attended Punjab University and Cambridge University, where he received his PhD in 1952. From 1951 to 1954 he was a professor of mathematics at the Government College of Lahore, concurrently with a post as head of the mathematics department of Punjab University. From 1954 until 1956 he lectured at Cambridge and from 1957 to 1993 he was a professor of theoretical physics at the Imperial College of Science and Technology, London. He was largely responsible for the establishment in 1964 of the International Center for Theoretical Physics, Trieste, as an institute to assist physicists from developing countries. He was director of the center from its inception until 1994, dividing his time between there and Imperial College.

Salam's work was concerned with the theories describing the behavior and properties of elementary particles; for this he received the 1979 Nobel Prize for physics, shared with Sheldon Glashow and Steven Weinberg. Although the three men did most of their work independently, they each contributed to the development of a theory that could take account of the ‘weak’ and ‘electromagnetic’ interactions. One of their predictions was the phenomenon of neutral currents and their strengths, which was first confirmed in 1973 at the European Organization for Nuclear Research (CERN) and later by other groups. A further prediction of the theory is that of the existence of ‘intermediate vector bosons’ with high masses. The discovery of a vector boson was reported in 1983 by two teams (comprising 180 scientists) working at the European Laboratory for Particle Physics near Geneva.