High Quality Content by WIKIPEDIA articles! Donald "Don" Zimmerman (born c. 1953) is an American lacrosse coach. He is currently serving as the head coach for the UMBC Retrievers at the University of Maryland, Baltimore County, a position he has held since 1994. Between 1984 and 1987, Zimmerman coached Johns Hopkins to three national championships. In 2009, The Baltimore Sun called him "the best coach in college lacrosse."