David Sklansky was born and raised in Teaneck, New Jersey, where he graduated from Teaneck High School in 1966. He attended the University of Pennsylvania, but left before graduation. He returned to Teaneck and passed multiple Society of Actuaries exams by the time he was 20, and worked for an actuarial firm.
Sklansky is generally considered a top authority on gambling. He has written many books on poker, blackjack, and general gambling.
Sklansky has won three World Series of Poker bracelets, two in 1982 ($800 Mixed Doubles, and $1000 Draw Hi) and one in 1983 ($1000 Limit Omaha Hi). He also won the Poker By The Book invitational event on the 2004 World Poker Tour, outlasting Phil Hellmuth Jr, Mike Caro, T. J. Cloutier, and Mike Sexton, and then finally overcoming Doyle Brunson.
Sklansky attended the Wharton School of Business at the University of Pennsylvania for a year before leaving to become a professional gambler. He briefly took on a job as an actuary before embarking into poker. While on the job he discovered a faster way to do some of the calculations and took that discovery to his boss. The boss told him he could go ahead and do it that way if he wanted but wouldn’t pass on the information to the other workers. "In other words, I knew something no one else knew, but I got no recognition for it," Sklansky is quoted as saying in Al Alvarez's The Biggest Game in Town. "In poker, if you're better than anyone else, you make immediate money. If there's something I know about the game that the other person doesn't, and if he's not willing to learn or can't understand, then I take his money."