Rohatgi served as founding director of the Regional Research Laboratories (CSIR) at Trivandrum and Bhopal, and as a professor at the Indian Institute of Science and the Indian Institute of Technology, Kanpur, where he pioneered incorporating renewable materials such as coir (fiber from the coconut shell), and banana and sisal plant fibers into polymer composites. He was running the research laboratory in Bhopal at the time of the gas leak disaster, but escaped unharmed and his lab was involved in studying the gas leak. He joined the University of Wisconsin–Milwaukee as a Professor in the Department of Materials Engineering in 1986, and is currently Wisconsin Distinguished Professor and Director, UWM Center for Composites.