Terry mentioned Dr. Johnson a few posts back. All the significant founders (except Washington and Jefferson) wrote for the newspapers. Franklin, Sam Adams and Hamilton published newspapers. The first American Crisis still makes Thomas Paine the greatest journalist who ever lived. The lede is as good as the Feast of St. Crispian speech in Henry V; better, because written on deadline.
Before all of these there was Henry St. John, Viscount Bolingbroke–our unacknowledged founding father, even though he never set foot here. If you look in your head, you will find his ideas–most of them pretty crappy ones too.
Luther and all the controversialists of the Reformation could be called public intellecutals. Jacob Burckhardt thought the founder of modern journalism was Pietro Aretino, the Italian pornographer and blackmailer (a portrait by Titian, I think, hangs in the Frick).