After working as a Special Agent with the Federal Bureau of Investigation, Gaffney moved to Suffolk County in 1973.
As an adjunct professor at the State University of New York at Stony Brook, he taught Public Policy and Administration in the Graduate School of Political Science from 2000 to 2003.
From 2004 until his appointment at Dowling in 2006, he was a partner at the Long Island law firm of Meyer, Suozzi, English & Klein, P.C.
[3] He has also served on the boards or committees of Central Suffolk Hospital and the Long Island Housing Partnership.
In 2005, Gaffney was appointed by Governor George Pataki to the New York State Commission on Healthcare Facilities in the 21st Century.