The expression second guess originated in big league baseball. In baseball, a man making a play has time only for one thought on that particular play. He must make up his mind in a flash how he is going to make the play. ... The expression came into the common speech because it so patly describes us fellows who sit back and analyze a wrong play after it has been made. [Damon Runyon, "The Brighter Side," Nov. 18, 1938]
The record of the phrase, at least in newspapers, seems to support the baseball origin. Second-guesser (1913) was baseball slang for "fan who loudly questions decisions by players, managers, etc.," and from about 1899 guesser or baseball guesser had been used in sports-writing for "fan who speculates and opines on the upcoming games or season."
Quisser is the new Texas league umpire. Guesser would be a better name for the majority of those who are now employed by president Allen. [El Paso Herald, June 14, 1911]