Prior to becoming a well-established tournament player Thomas Preston, widely known as "Amarillo Slim", was a rounder, joining the likes of Johnny Moss and Doyle Brunson before him, traveling the US in search for gambling action.

In 1973, Thomas Preston along with Bill G. Cox wrote a book entitled "Play Poker to Win", this was published by Grosset and Dunlap. In 2005, the original work would be revised and renamed "Amarillo Slim's Play Poker To Win", and was published by Harper Collins. The book became a best-seller and it reveals a very useful information not just about poker, but other casino games too.

After his WSOP victories, he appeared on many talk Shows and in 1974 had a minor part in "California Split", a movie by Robert Altman. Preston also appeared on the TV show called "I've Got a Secret", where he revealed having once lost $190,000 all in a single night, whilst playing the game that he loved.

In the first two months of 1980, Amarillo Slim hosted the prestigious Second Annual Poker Classic which at that time was the country's second most prominent tournament. The series would go on to be renamed the Super Bowl of Poker, with Gabe Kaplan becoming its first winner and Stu Ingar winning the coveted title three times.

Preston would go on to win four World Series of Poker bracelets along with two in Omaha. His last WSOP win occurred in 1990, and in the 2000 WSOP Omaha event he came second only to the legendary Phil Ivey, with total tournament earnings topping over half a million dollars.

In May of 2003, Preston was on the writing trail again, this time to publish an autobiography which was called "Amarillo Slim in a World Full of Fat People".

In the book he would recount tales the likes of playing Poker with former US Presidents Richard Nixon and Lyndon B. Johnson, and go on to expand his other Poker exploits including that of Proposition betting. Proposition bets are seemingly crazy side bets had at the Poker table, and Slim certainly had his unique take on the topic!

A biopic movie based upon this autobiography of Thomas Preston was reportedly to be in the making with Nicolas Cage playing Preston in the movie. However a Poker Listings article in 2009 claimed that the planned Hollywood movie based upon his life story had been dropped. Sadly 3 years later, he passed away with cancer of the colon, Preston was aged 83.