A printable list of past World Series winners and results throughout MLB history. The MLB playoffs close with the World Series which was first played in 1903 and has been held every year except for 1904 and 1994. The World Series is played with the Champion of the American League and the Champion of the National League in a best-of-seven series. In 1903, 1919, 1920, and 1921, the World Series Champion was decided in a best-of-nine series. The World Series Champions would receive the Commissioner's Trophy and World Series rings.