Tom Costello is the second oldest of five children born to Margaret (nee Flynn) from County Galway and Patrick Costello from County Roscommon. Tom was raised in Sunset Park, Brooklyn, and was educated at Manual Training High School in Brooklyn. Upon graduation, Tom joined the United States Marine Corps Reserve and completed six years of military service. In 1961, Tom was appointed to the New York City Police Department and during his time with the Department, he was awarded a Certificate of Achievement by the American Legion Post 159 as Police Officer of the Year. After seven years of service with the Police Department, Tom transferred to the New York City Fire Department and retired from active service in 1984. Tom has been an ordained member of the Order of Deacons since 1988 following his studies at the Diaconate at the Immaculate Conception Seminary in Huntington, New York.

Tom is Chaplain of the Hewlett Bay Fire Department as well as the Chaplain of A.O.H. Division #3 Five Towns and the A.O.H. Nassau County Board. Tom is very active in Saint Joseph’s Church, Hewlett, NY and in 2008 he was nominated to receive the Saint Agnes Award Medal. Tom coaches baseball in the Valley Stream Male League and the Hewlett Little League. Tom and his wife, the former Martina McNicholas, were married in 1969 and they are the proud parents of five wonderful children, four boys and one girl, and seven granddaughters.