Dr. Petersen received his B.Sc. Honours in Chemistry from The University of Western Ontario in 1972. He went on to receive his PhD in Chemistry with a minor in Biology from the California Institute of Technology in 1978. After postdoctoral positions at Cornell University and Washington University Medical School, he returned to The University of Western Ontario's Department of Chemistry as a faculty member in 1981. He was Chair of the department from 1995 to 1999. From 1993 to 1995, he was Associate Dean of the Faculty of Graduate Studies; from 1999 to 2000 he served as Associate Vice-President (Research) and Acting Vice-President (Research).

Dr. Petersen was the Director General of the National Institute for Nanotechnology until July 2011, having joined the National Research Council and the University of Alberta in 2004 after three years as Vice-President (Research) at the University of Western Ontario.

At the University of Alberta, Dr. Petersen was Professor of Chemistry from 2004-2014 and served as Acting Associate Dean of Science (Research) from 2011-2012.

Dr. Petersen is a Fellow of the Chemical Institute of Canada. He currently serves as a member of three boards of notfor-profit organizations including Compute Canada, TECTERRA, and the Canadian Light Source (CLS) for which he is Chair of the Board. He recently finished terms as a member of the boards of ArboraNano, a Business-led NCE, the California Nanosystems Institute (CNSI), and the Pacific Institute for Mathematical Sciences, and as Chair of the Board of NSERC’s Strategic Network program BiopSys at the University of Toronto.

Dr. Petersen's recent research in membrane biophysical chemistry focused on intermolecular interactions in biological membranes, particularly the study of the dynamics and distribution of molecules within the membrane; on the function of lung surfactants in healthy and diseased lungs, and on characterization of nanoparticles and their interaction with cell surfaces. In 2017, he published a textbook for students entering the fields of nanoscience and nanotechnology from disciplines other than physics and physical chemistry called “Foundations for Nanoscience and Nanotechnology”.