Deputy John Greeney III joined the Broward Sheriff's Office in 1986 after serving in the United States Air Force as a security officer. He graduated from Broward County's 121st Police Academy and received its Honor Medallion, awarded to the most outstanding member of the graduating class. He was initially assigned to BSO's Unincorporated Central Broward County district and later became a field training officer.
On February 17, 1990, Deputy Greeney responded to an armed robbery at a fast-food restaurant west of downtown Ft. Lauderdale and was fatally shot. Two men were convicted for his murder; one is serving a life sentence and the other is awaiting execution on Death Row. Deputy Greeney was interred with full honors at Arlington National Cemetery.
Deputy Greeney's career in law enforcement continued a proud family tradition: his father was a member of the Broward Sheriff's Office as well.