He worked briefly with the WNTV-WNBS (1965-1966), in Ibadan as a pupil engineer before proceeding to Ahmadu Bello University in 1966. In January, 1968 he joined the University of Lagos as an assistant lecturer and rose to the position of Professor in October 1983. He has worked in the area of electronic circuits and semi-conductor devices, energy, renewable and solar energies, and energy management and auditing; where he published most of his works. His work in distributed parameter networks resulted in the development of micro-miniaturized devices for use in airborne systems, satellites, and space technologies. Part of his work has led to the development of active all-pass networks using the least number of components and consequent reduction in manufacturing cost. He was one of the first group of researchers to design a system to find and track the sun (solar tracker) on the continent of Africa.
Professor Salawu was an associate at the International Center for Theoretical Physics in Turin, Italy, a visiting scientist at Concordia University, in Montreal Canada, visiting Professor at Kyung Hee University, Seoul, South Korea, and visiting Professor at the University of Botswana, Gaborone. He was appointed UNESCO visiting Professor of Electronics to prepare a new program for the Electrical Engineering Department of the University of Liberia, Monrovia after the war in that country. He has been consultant to UNESCO, UN-ECA, OAU and the European Union. For some time, he was the chairman of the OAU-Scientific, Technical and Research Commission, committee on new, renewable and solar energies. For a period of five years he served as the Africa representative on the American Association for the Advancement of Science committee on Science and Technology for Development. He was at one time the Secretary-General of the Nigerian Society of Engineers, its Vice President, Honorary Secretary of the Nigerian Academy of Science and Registrar of the Council for the Regulation of Engineering in Nigeria (COREN). He is currently Professor in the College of Engineering at Bells University of Technology, OTA. He is a Fellow (one of the first set of fellows) of the Solar Energy Society of Nigeria, Fellow of the Nigerian Society of Engineers, Fellow of the Nigerian Academy of Science and a Foundation Fellow and Foundation Secretary, and later Technical Secretary of the Academy of Engineering.