Born in Pittsburgh, Gage attended Central Catholic High School, then studied at Wheeling Jesuit University.
[1] In 1968, he became a professional baseball player, a catcher with the Baltimore Orioles, having been drafted in the 5th round, but did not play in a major league game, and was released at the end of the season.
[2] In 1974, Gage became a disability examiner for the Social Security Administration (SSA), and joined the American Federation of Government Employees (AFGE).
He stood down as national vice president in 1985, to focus on organizing SSA employees, against an attempt by another union to represent them.
As leader of the union, he focused on organizing new members, and arranging agreements with employers, the last one being with the Transportation Security Administration.