McEvoy was born and raised in Michigan. He was an accountant, but after he was laid off from his job, he took up poker full time in 1978. He first learned to play poker when he was five years old and would regularly get in trouble for playing it in grade school.

McEvoy first cashed in the WSOP in 1982, finishing in 6th place in the $1,000 Razz event. The following year, he won his first World Series of Poker bracelet in the $1,000 Limit Hold'em event, defeating Irish professional poker player Donnacha O'Dea heads-up to win the tournament.

McEvoy won the 1983 World Series of Poker Main Event. He was the first winner to earn his buy-in through a satellite tournament. His heads-up matchup with Rod Peate was the longest heads-up battle in WSOP history before being surpassed during the $50,000 H.O.R.S.E event in 2006 by Chip Reese and Andy Bloch.

Since his two bracelet wins in 1983, McEvoy has gone on to win two more WSOP bracelets. He won the Razz tournament in 1986, defeating Alma McClelland, and a Limit Omaha tournament in 1992, defeating 1986 world champion Berry Johnston. But his luck in the WSOP Main Event since his championship win has not been so good. McEvoy's only other main event cash since 1983 was in the 2006 WSOP, when he finished in 371st place, earning $34,636.

In March 2006, Tom McEvoy won the third ever Professional Poker Tour event beating a field of pros-only at the Bay 101 casino. He defeated a final table that included fellow WSOP bracelet winners, Toto Leonidas and Hoyt Corkins.

McEvoy is staunchly opposed to smoking. In 1998 he helped organize the first tournament where smoking was not allowed. There was much reluctance, but the tournament still attracted a large number of players, and therefore confirmed the viability of having non-smoking tournaments. Also, in 1998, McEvoy won the annual Ventura County poker championship, with Phil Palmquist finishing in third place. Palmquist began this Omaha tournament with a Royal Flush, which brought him to the final table as Chip Leader, only to be "worn down" by McEvoy. In 2002 he convinced Becky Binion Behnen to make the WSOP a non-smoking tournament by agreeing to give Behnen poker lessons.

McEvoy has authored or coauthored over a dozen books on poker with other players such as T. J. Cloutier, Brad Daugherty, Don Vines, and Max Stern. He is a columnist for CardPlayer Magazine and a representative of PokerStars.com, where he can be seen playing under his own name.

On Sunday May 31, 2009, Tom McEvoy became the winner of the WSOP's first Champions Invitational, outlasting 19 other former Main Event champions. He defeated 2002 world champion, Robert Varkonyi in the heads-up play to win the tournament. The first prize was a Classic 1970 Corvette and the inaugural Binion Cup, presented by Jack Binion, in honour of his father, Benny Binion, the founder of the WSOP and Binion's Horseshoe, the original home of the World Series.

As of 2010, his total live tournament winnings exceed $2,900,000. His 38 cashes at the WSOP account for $1,297,410 of those winnings.

McEvoy resides in Las Vegas and has three children.