Nor was it invented by Abner Doubleday. They gave the credit to Abner Doubleday, a Civil War hero who allegedly invented the game in Cooperstown in 1839. The truth is, Doubleday wasn’t even a fan of the sport, much less its creator. Variations on baseball have been around since the 18th century, from children’s games like rounders to cricket. Baseball as we know it today was the brainchild of New Yorker Alexander Joy Cartwright, a volunteer firefighter and bank clerk who came up with the three-strike rules, the diamond-shaped infield, and all the foul lines.