County Executive Kathleen Falk issued a news release saying the center's director, Joe Norwick, will step down Sept. 19.
Falk praised Norwick for initiating upgrades in the 911 center and coordinating the establishment of a $30 million emergency radio center.
But Norwick also was in charge at the time University of Wisconsin-Madison student Brittany Zimmermann was slain in her off-campus apartment.
Authorities said a 911 call came in from Zimmermann's cell phone around the time she was attacked, but a dispatcher lost contact, didn't call back and didn't send police to investigate.
The murder remains unsolved.

