Moss was born on May 14, 1907 in Marshall, Texas and grew up in Dallas, Texas, which was where he learned how to gamble as a young boy. A group of cheaters taught him how to cheat in games, but Moss put this knowledge to good use. As a teenager, he was hired by a local saloon to watch over games and make sure they were played fairly. While he was keeping games safe from cheaters, he was learning the strategy behind playing poker.

In 1949, Moss played with Nick the Greek in a five-month-long “heads up” poker marathon set up by mob boss Benny Binion, winning between $2 and $4 million. At the conclusion of the game, Nick the Greek uttered what has become one of the most famous poker quotes ever: “Mr. Moss, I have to let you go.” This game is often cited as the inspiration behind the WSOP. This game became the foundation for Al Alvarez’s book The Biggest Game in Town and is one of the best known stories in poker. Despite being one of the best-known poker stories, a soon to be released book, Showgirl Stories, by Steve Fischer claims the game never took place. According to Fischer, there were no stories or reports of this tournament until six years after Nick’s death. Binion never spoke of the game even when providing a detailed history of Las Vegas and avoided answering questions about the game by saying, “Well, my memory ain’t what it used to be.” While Nick the Greek was often covered by the national media, there are no news reports in any local or national source. Fischer says that nearly every version of the story is virtually identical to the version first told by Moss beginning circa 1971. The story is consistently said to have taken place in 1949 at the Horseshoe Casino, a casino that did not exist for another year and a half. Fischer also points out that during the time that Binion supposedly set up the game, he was fighting off a request from Texas to have him extradited. Because of his past, Binion lost his license to run a gambling establishment in 1948 and did not regain it until April 13, 1950. He was not granted a license to open the Horseshoe Casino until December 5, 1952. Fischer believes that the notion of Binion sponsoring a poker game, in front of a window, of a casino that had not opened, while fighting extradition is “absurd.”

In reaction to a 2017 pokernews.com article on the topic, Jack Binion, at the time 80 years old, attempted to clarify. To address the heart of the matter first, Binion explained that Johnny Moss and Nick Dandolos did play a poker match in 1949, although it was not at the Horseshoe at all. Nor was it the months-long spectacle open to spectators many have suggested the match to have been.

“There was a big game at the Horseshoe in the early ’50s,” Binion explained, “but Nick didn’t participate.” The game featured “multiple players” including Moss, who came and went as the game continued around the clock. Unlike the game at the Flamingo in 1949, the later one “was held in public.”

In 1970, Moss was voted champion by his peers and was awarded a silver cup.