Tufnell was educated at Highgate School where his cricketing prowess was recognised and he was appointed captain of the Junior School's First XI despite the fact he was not yet in the top year. On leaving Highgate, he attended and played cricket for Southgate School. He then trained in quantity surveying and was faced with the tough decision of whether to play cricket professionally or to work as a quantity surveyor. He chose to do the former.

As a slow left-arm orthodox spin bowler, Tufnell played 42 Test matches and 20 One Day Internationals for England between 1990 and 2001, and 316 first-class matches, mainly for Middlesex. Tufnell was occasionally inspired with the ball, taking 11–93 against Australia at the Oval in 1997 (for which he won the Man of the Match award after England won by 19 runs) and seven wickets in the match (6-25 in the first innings) against the West Indies at the Oval in 1991, but he took his 121 Test wickets with a bowling average of 37.68 across his whole Test career. Mark Waugh theorised that "if you attack him, he can go on the defensive, and it puts him off his game", although Waugh was Tufnell's most frequent test victim, being dismissed a total of seven times by him, three of them bowled. According to Michael Parkinson, a British talk show host, "at the age of nine he was opening the bowling and the batting for his club's junior team". Parkinson also believes that his "ordinary fielding made him a luxury in the view of the ... (English cricket) management (circa August 1996)". However, Tufnell's fielding did improve during his career. He was nicknamed "The Cat" due to his propensity to be found sleeping in the dressing room. He also acquired the nickname "Two Sugars" due to his well-known love of tea. According to England teammate Mike Atherton, Tufnell smoked more than occasionally.

During his career spanning over a decade with Middlesex, Tufnell took more than 1,000 first-class wickets in the English game. His autobiography What Now ? ISBN 0-00-218816-3 was published in 1999.

Tufnell also received an honorary doctorate from Middlesex University on 20 July 2011 in recognition of his achievements in sport and the media.