John R. (Jack) Howell received his academic degrees from Case Western Reserve University (then Case Institute of Technology), Cleveland, Ohio. He began his engineering career as a researcher at NASA Lewis (now Glenn) Research Center (1961–1968) and then took academic positions at the University of Houston (1968–1978) and the University of Texas at Austin in 1978, where he remained until retirement in 2012. He is presently Ernest Cockrell, Jr., Memorial Chair Emeritus.

He pioneered the use of the Monte Carlo method for the analysis of radiative energy transfer in complex systems that contain absorbing, emitting, and scattering media. Jack concentrated his research on computational techniques for radiative transfer and combined-mode problems for over 60 years. He has adapted inverse solution techniques to combined-mode problems and to radiation at the nanoscale. His awards include the NASA Special Service Award (1965), AIAA Thermophysics Award (1990), ASME Heat Transfer Memorial Award (1991), ASME/AIChE Max Jakob Medal (1998), the Poynting Award from JQSRT (2013) and the International Center for Heat and Mass Transfer Luikov Medal (2018). He was elected to the U.S. National Academy of Engineering (2005) and as foreign member of the Russian Academy of Sciences (1999). He is an Honorary Fellow of the American Society of Mechanical Engineering (ASME).

Jack served as ME Department Chair (1982-86) and Associate Dean for Research in the Cockrell School (1988-91), as well as Director of various Research Centers.