Spahn led the NL in wins 8 times, ERA 3 times, complete games 9 times, shutouts 4 times, innings pitched 4 times, strikeouts 4 times and WHIP 4 times. He did this, for the most part, pitching on bad Boston and Milwaukee Braves teams (for the exception of the 1948, 1957 and 1958 teams that won a World Series and 2 NL Pennants).
I always make the joke of Spahn being one of the ten Hall of Fame players to wear a Mets uniform. Of course, when he joined the Mets, his career was finished. He was traded to the San Francisco Giants where he enjoyed a little bit more success before retiring after the 1965 season.