Bill Zimmer advances from inspector to chief within the San Teresa Metropolitan Police Department after his predecessor Jack Roth's removal. His career transitioned from prior military service with the United States Marine Corps into law enforcement.

Zimmer displays a boisterous, energetic leadership style marked by Seventies-style facial hair and emphatic gestures. Despite this outward exuberance, he acts as a reasonable authority figure, delivering insightful guidance and steadfastly backing his subordinates during investigations.

He prioritizes camaraderie and morale, hosting weekend gatherings for department members at his residence. This practice cultivates loyalty and solidifies his role as a supportive pillar within the force.