#9 - ‘Welcome Back, Kotter’: John Travolta might be best know for his movie career, but many of his fans first came to know and love him in the ‘70s high school series, ‘Welcome Back, Kotter,’ which ran from 1975-1979. The show chronicled the return of a wisecracking teacher, Mr. Kotter (played by Gabe Kaplan), who returned to his high school alma mater and attempted to teach and mentor a group of troublemakers know as the ‘Sweathogs,’ which included a young Travolta.