Barry Greensteien was born in Chicago, Illinois, on December 30^th 1954. He started playing the game at a very young age and was introduced to poker by his father, who had been a regular player while he was in the army.

He graduated from the University of Illinois at Urbana-Champaign with a bachelor's degree in computer science. He started studying for a PhD. in Mathematics, but did not complete his dissertation.

Before starting to play poker full time, he worked for Symantec. He left the company in 1996 to pursue his poker career.

Greenstein, who is nicknamed 'The Robin Hood of Poker' because of his tendency to donate his winnings to charity, has enjoyed a lot of success in the World Series of Poker. He has two bracelets, and has racked up 31 money finishes over the course of his career.

Greenstein has also achieved two World Poker Tour titles ($5,000 No Limit Deuce to Seven Draw in 2004, and $1,500 Pot Limit Omaha in 2005), and has appeared on three series of the Poker Superstars Invitational Tournament, and four series of the GSN show High Stakes Poker.

Greenstein has written a book, titled Ace on The River. He often gives a free, signed copy of the book to players that manage to eliminate him in a tournament. He writes into the book the details of the hand that was just played. The World Poker Tour Season 3 champion, Tuan Le, credits Greenstein's book with helping him succeed on the poker tournament circuit.

He taught his ex girlfriend, Mimi Tran, how to play poker as a thank-you for her teaching him the Vietnamese language.

Greenstein plays online at the PokerStars website, where he has the user name 'barryg1'. He is a member of the sites' Team Pokerstars.

Greenstein has won more than $5 million from live tournaments so far. Early in his career, he donated almost all of his winnings to the charity 'Children, Incorporated'. He now supports a variety of children's charities, although Children, Incorparated is still the main beneficiary.