Tom was appointed Lindenhurst Village Trustee in May 1999 to fill a vacancy and was elected in March 2000 for a full four-year term as Trustee. He successfully ran for Mayor of the Village of Lindenhurst in March 2004 after the retirement of Mayor Lynda Distler. Tom was re-elected in 2008, 2012 and again in 2016.
He has been a Village of Lindenhurst resident for nearly 50 years. He is married and has raised three children. He also has two grandchildren.
In addition, Tom is a Navy veteran and a member of the American Legion Post, Rotary International and Kiwanis Clubs, Lindenhurst Historical Society, the Knights of Columbus OLPH Council 794, the Ancient Order of Hibernians, as well as the Loyal Order of Moose. He also serves as a Lindenhurst National Little League Executive Board Member, a Director and a Manager.
Mayor Brennan is also a local businessman, serving as a director of the Lindenhurst Funeral Home, as well as a member of the Lindenhurst Chamber of Commerce.
He was the 2010 winner of the Pride of Lindenhurst Award presented by the Lindenhurst Board of Education. He was also the 2009 winner of the Knights of Columbus OLPH Council 794 Irishman of the Year Award.