Eddie Cochem, the Saint Louis University coach, was the first to use the forward pass in 1906. It wasn't legalized in the NFL until 1933.
Here is more input:
- No one really knows when exactly the first forward pass was implemented in an actual game, but most historians do agree that in 1873 represenatives from Yale, Princeton, and Rutgers met to discuss formulating rules for this new game of football. The new rules consisted of reducing the number of men on the field from fifteen to eleven. Adding a fourth down before surrenduring the ball. Tackling below the waist was allowed. And lastly, the forward pass was legalized behind the line of scrimmage. The NFL/AFL merger did not happen until 1970. But by then the forward pass was an intricate part of the game.