Amarillo Slim, the pencil-slender, cornpone-spouting Texan who became poker’s first superstar by overpowering opponents with charm, cunning and preternatural coolness, died on Sunday in Amarillo, Tex. He was 83.

The cause was colon cancer, his son, Thomas Preston III, said.

After honing his gambling skills as a pool hall hustler and illegal bookmaker, Thomas Austin Preston Jr. turned his attentions to poker in the 1960s, when it was played mainly on kitchen tables and in smoky backrooms and Las Vegas casinos. With his cowboy hat and boots, Texas drawl and country wit, he became the public face of poker as he won major titles at a time when the game was rising to a multibillion-dollar mainstream business, first on television and then on the Internet.

“Slim used his name and face to promote poker in a way it had never been done before, and without Amarillo Slim, the poker world would likely not exist in the way we know it today,” Poker Player News said in its obituary.

Amarillo Slim won five times in World Series of Poker events, was elected to at least four gambling halls of fame and played poker with Presidents Lyndon B. Johnson and Richard M. Nixon, the drug lord Pablo Escobar and the magazine publisher Larry Flynt, who dropped $1.7 million.