Muhlstein has worked as an engineering consultant at Exponent, Inc. (Failure Analysis Associates). In September, 2002 he joined the faculty in the Department of Materials Science and Engineering at The Pennsylvania State University and was tenured and promoted to associate professor in 2008.

 Muhlstein’s research focuses on understanding the mechanisms of fracture and fatigue in bulk and thin film materials. Muhlstein is a member of Alpha Sigma Mu and Keramos honor societies and an NSF CAREER award recipient. In 2007 he was also named the Corning Research Faculty Fellow in Materials Science and Engineering at The Pennsylvania State University.