Keenan joined the GBI in 1973 and was appointed director of the agency in January 2003 by Governor Sonny Perdue. Prior to joining the GBI, he served as a patrolman with the DeKalb County Police Department (November 1972 - June 1973).
Keenan's career path involved joining the GBI in 1973 and becoming its director under Governor Sonny Perdue in January 2003, after having previously worked as a patrolman for the DeKalb County Police Department from November 1972 to June 1973.