Thomas Joseph Ridge (born August 26, 1945) is an American politician who served as a member of the United States House of Representatives (1983–1995), Governor of Pennsylvania (1995–2001), Assistant to the President for Homeland Security (2001–2003), and the first United States Secretary of Homeland Security (2003–2005). Since re-entering the private sector, Ridge has served on the boards of The Home Depot and The Hershey Company and as a senior advisor to Deloitte & Touche, and TechRadium. Ridge is also the founder and CEO of Ridge Global, LLC, a Washington, D.C. based security consulting firm. Ridge spent time campaigning with fellow Republican, Senator John McCain during his 2008 bid for the presidency and was believed by some to have been in the short list of potential running mates. Ridge wrote in his memoir that then-Secretary of Defense Rumsfeld and then-Attorney General Ashcroft pressured him to raise the terror alert level, running up to the 2004 elections, based upon information they had received.

Ridge was born in Munhall, Pennsylvania, in Pittsburgh's Steel Valley, the oldest of three children. His parents were Laura (née Sudimack) and Thomas Regis Ridge, who was a traveling salesman and Navy veteran. Ridge's maternal grandparents were Ruthenian immigrants from the former Czechoslovakia and his paternal great-grandparents emigrated from Great Britain. Ridge was raised in veterans' public housing in Erie, Pennsylvania. He was educated at St. Andrews Elementary School and Cathedral Preparatory School and did well both academically and in sports. He earned a scholarship to Harvard College, where he paid his way through with construction work, played intramural baseball and football, and graduated with honors in 1967.

After his first year at the Dickinson School of Law, he was drafted into the United States Army, where he served as an infantry staff sergeant during the Vietnam War. He earned the Bronze Star, National Defense Service Medal, Vietnam Service Medal, Vietnam Campaign Medal, Vietnam Gallantry Cross Unit Citation with Palm, and the Combat Infantryman Badge. Later he was offered a position as an officer but turned it down when he learned that it would require an extra year of service.