Chief G. Matthew Immler began his law enforcement career with the Baltimore Police Department in 1974 after serving four years in the United States Navy. His first assignment was as a foot patrol officer in the city's Northwestern District. After spending a year on foot patrol and two years on motorized patrol, he was transferred to the department's Tactical Operations Division where he became a member of the agency's first SWAT team. Chief Immler advanced to the rank of lieutenant and served as director of the police academy and as operations and administrative commander in two of the city's patrol districts prior to his retirement in 1994. Chief Immler earned many departmental special awards, including the Silver and Bronze Star. In addition to attending numerous professional training programs, Chief Immler earned a Bachelor of Science degree in criminal justice from the University of Baltimore, a Masters of Liberal Arts degree from the prestigious Johns Hopkins University and a Juris Doctorate degree from the University of Baltimore School of Law. He is currently licensed as an attorney and a member of the bar in both Maryland and Florida.

After retirement from the Baltimore Police Department, Chief Immler served as an attorney for various Fraternal Order of Police Lodges throughout the State of Maryland, and represented officers in disciplinary matters, criminal cases and labor negotiations. He and his family moved to Florida in 1999 when he was appointed as the Assistant Chief of Police for the Boynton Beach Police Department. Chief Immler was tasked with reorganizing the agency and guiding it through the accreditation process, which was successfully completed in 2001 when Boynton Beach became the 84th accredited agency in the state.

In 2005, Chief Immler was appointed to his current position. Additionally, Chief Immler serves as the Immediate Past President of the Palm Beach County Chiefs of Police Association, Chairman of the Palm Beach County Law Enforcement Planning Council and as a member of the Florida Department of Law Enforcement Criminal Justice Information Systems Council and the Department of Juvenile Justice Blueprint Commission.

On September 2, 2005, Chief Immler was sworn in as The City of Boynton Beach's 30th Police Chief.