Jeff Ma or Jeffrey Ma was a member of the MIT Blackjack Team in the mid-1990s. He graduated from Phillips Exeter Academy. He attended MIT where he graduated with a degree in mechanical engineering in 1994. He was the basis for the main character of the book Bringing Down the House (where he was renamed Kevin Lewis) and the film 21 (where he was renamed Ben Campbell). Ma also co-founded PROTRADE (a sports stock market website, that has since been shut down) and does consulting work for professional sports teams including the Portland Trail Blazers and San Francisco 49ers. He cofounded Citizen Sports, a sport-information website and iPhone application based in San Francisco, which was acquired by Yahoo! in May 2010.

His first book, The House Advantage: Playing the Odds to Win Big In Business, was published in July 2010 by Palgrave Macmillan. Ma is a regular speaker at corporate events and conferences where he talks about how to use data and analytics to make better business decisions.[5]

Ma makes a cameo in 21 as a blackjack dealer named Jeffery at the Planet Hollywood Resort and Casino.[6][7] Jim Sturgess's character, Ben Campbell, refers to Jeffrey as, "my brother from another mother."

Ma is currently the CEO and Founder of tenXer, a San Francisco based startup, with the vision to "make work better and your work better"

As part of the notorious MIT Team depicted in Ben Mezrich’s now classic Bringing Down the House , Jeff Ma used math and statistics to master the game of blackjack and reap handsome rewards at casinos. Years later, Ma has inspired not only a bestselling novel and hit movie, but has also started three different companies—the latest of which, Citizen Sports, is an innovative marriage of sports, betting, and digital technology—and launched a successful corporate speaking career. The House Advantage reveals Ma’s cutting-edge mathematical insights into the world of statistics and makes them applicable to a wide business audience. He argues that numbers are the key to analyzing nearly everything in the world of business, from how to spot and profit from global market inefficiencies to having multiple backup plans in anticipation of every probability. Ma’s stories and business lessons are as intriguing as they are universally applicable.