Chief McKenna began his career with the Middletown Township Police Department in April 1957 after receiving his basic training at the Philadelphia Police Academy. In 1959, he was promoted to the rank of Detective, graduated from the FBI-PCPA Inter-County Detective School, and was assigned to burglary investigations. In 1963, he was promoted to the rank of Sergeant and was assigned as a supervisor of one of the four patrol squads.
He attended Penn State's Polex and Posit supervisor schools. In 1966, he was assigned the commander of the Criminal Investigation and Juvenile Division and after five years supervising criminal investigations, was promoted to the rank of Lieutenant. As Lieutenant in the Patrol Division, he was assigned as night commander. Lt. McKenna in 1974 was assigned Community Crime Prevention and attended the National Crime Prevention Institute conducted by the University of Louisville. Lt. McKenna worked with the Lower Bucks Community Center and Elwood Cronk to develop over 120 SNAP (Safer Neighborhoods Are Possible) groups in the Township which resulted in 62% reduction in residential burglaries. Lt. McKenna was named "Police Officer of the Year" in 1986 by the Lower Bucks Chamber of Commerce for his community crime prevention work.
After training at the University of Delaware in K-9 unit management, Lt. McKenna was assigned supervision of the Township's four team K-9 Unit and the construction of the K-9 kennels. Lt. McKenna was a firearms instructor for the Department from 1980 to 1988 and in 1987 developed and formed Middletown's YAP (Youth Aid Panel) program. In 1988, Lt. McKenna was appointed as Interim Chief and in February 1989 was appointed Chief of Police. Chief McKenna is a graduate of the FBI National Academy in Quantico, Virginia and a member of the National Academy Associates. In 1990, the Exchange Club of Levittown named Chief McKenna "Officer of the Year" for his work in crime and drug abuse prevention.
The Chief is a member of the Police Chief's Association of Bucks County, Pennsylvania Chiefs of Police Association, Police Chief's Association of Southeastern Pennsylvania, the International Association of Chiefs of Police, and the National Association of Chiefs of Police, and has been a member of the Fraternal Order of Police since 1958.