Shadix was a second cousin of a film executive Thomas Rothman and an actor John Rothman.
In his early years, Glenn traveled and lived all over Alabama, Tennessee and Florida's Gulf coast.
Shadix provided the voice for the Mayor in the movie The Nightmare Before Christmas (1993).
Glenn: In those early days my entire, and quite large, family all gathered around the set at night and gave Uncle Miltie, Lucy and Desi and George and Gracie their undivided attention. From my earliest memory I decided I was somehow going to get inside that box and make my family laugh like they laughed at Lucy and cry like they did with Playhouse 90 dramas.