It was at the latter utility that he became part of their then-new environmental planning staff in 1970, being influenced by the first Earth Day in May 1970.

Dr. Mitsch has authored or co-authored over 600 papers, books, published abstracts and other publications in ecological and environmental science.

Mitsch has served on committees of the Science Advisory Board (SAB) of the U.S. Environmental Protection Agency (2001–2011) and on several United States National Research Council (NRC) committees of the National Academy of Sciences (1991–2004).

Among his awards, Mitsch and his colleague and frequent co-author Sven Jørgensen of Denmark received the 2004 Stockholm Water Prize[7] from King Carl XVI Gustaf of Sweden on August 19, 2004, in Stockholm, Sweden.

He also received the National Wetland Research Award (1996) from the U.S. Environmental Protection Agency and Environmental Law Institute, the Theodore M. Sperry Award (2005)[8] for a career in ecosystem restoration from the Society for Ecological Restoration, a SWS Lifetime Achievement Award (2007)[9] from the Society of Wetland Scientists (SWS), an Einstein Professorship from the Chinese Academy of Sciences (2010), and The Ramsar Convention Award for Merit presented at Ramsar Committee of Party (COP) 12th Congress, Puenta del Este, Uruguay on June 3, 2015.