Prof. Ashok Jhunjhunwala’s first appointment was in Washington State University, USA from 1979 to 1980. Prof. Jhunjhunwala then joined IIT Madras in 1981 in the Department of Electrical Engineering. Over the last few decades he has looked at the cost and affordability of various components of the telecommunications and the Internet network, especially in the Indian context. He has worked on techniques to enable communication networks to reach remote parts of rural India. In recent times, he has made some significant contributions in Solar-DC and in battery systems for Electric Vehicles. He has guided more than 70 M.S. and Ph.D. students.

Over the course of his career Jhunjhunwala has served as Chairman and member of various government committees. He has been on boards of several private companies and educational institutions in the country. He was on the boards of the State Bank of India, Bharat Electronics Ltd, Hindustan Teleprinters Limited, NRDC, Institute for Development and Research in Banking Technology (IDRBT), VSNL and BSNL as well as Tata Communications, Mahindra Electric, Sasken, Tejas Networks, Tata Teleservices Maharashtra Ltd, Intellect and Exicom. As of 2020 he is on the board of Biotechnology Industry Research Assistance Council (BIRAC), Chairman of IIITH and is the Chairman of Technology Advisory Committee of SEBI In 2017 - 18, Jhujhunwala was on sabbatical from IITM, serving as the Principal Advisor to the Ministry of Power in the Government of India, and the Ministry of Railways in the Government of India, New Delhi.