[1] Prior to becoming an analyst, he served as the head coach for the UMBC Retrievers at the University of Maryland, Baltimore County for 24 years.
While there, the lacrosse team on which he played won three Maryland Interscholastic Athletic Association (MIAA) championships.
The following year, the Blue Jays compiled a 10–2 record, and were eliminated in the semifinals in overtime by the eventual national champions, North Carolina.
[4] Former Hopkins head coach Dave Pietramala spent his entire college playing career under Zimmerman, from 1986 to 1989.
[10] Zimmerman spent three years at Loyola as an assistant for the Greyhounds under Dave Cottle, before he was hired as head coach by the University of Maryland, Baltimore County (UMBC).
In 1998, the Retrievers delivered a major upset by beating, 12–8, then first-ranked Maryland, the eventual national championship runners-up.
[12] In 2007, UMBC again advanced past Binghamton before falling to Albany in the America East championship game, and secured another berth in the NCAA tournament.
[12] In June, he was considered the frontrunner to replace John Haus who had been fired as North Carolina's head coach, but Zimmerman removed his name from consideration.
[18] While coach at UMBC, Zimmerman has traveled to Japan, Argentina, and the United Kingdom in order to promote the sport of lacrosse.
Regarding the possibility of the sport being a future Olympic event, Zimmerman said, "It’s incumbent upon us to introduce and develop the game when opportunities occur in order to reach that goal.
"[4] The Greater Baltimore Chapter of the United States Lacrosse Hall of Fame inducted Zimmerman on January 25, 2003.