Hunter was educated at St Andrews Primary School and Cardinal Heenan High School in Leeds. With some encouragement from friends and family, he spent many hours practicing snooker, and by the age of 12 had become an outstanding junior talent. With the help of former professional snooker players Jimmy Michie and Joe Johnson, the youngster from Leeds made his debut among the professionals in July 1995 at the age of 16.

Four months later, Hunter caused a major sensation at the UK Championship by beating world number six Alan McManus 9-4 in the first round. He followed up that achievement by becoming the youngest player to reach the last four of a ranking event when he reached the semi-finals of the 1996 Regal Welsh Open at the age of just 17 and three months.

Also in 1996, he reached the quarter-finals of the UK Championship where he beat Willie Thorne 9-0, James Wattana 9-5 and Terry Murphy 9-7 before bowing out 9-5 to eventual champion Stephen Hendry. Hunter's achievements earned him high accolades throughout the game and was awarded a wildcard to play at the 1997 Benson & Hedges Masters. Although he was beaten 5-1 by Mark Williams in the first round, it was to be the start of a great love affair that he would have with Wembley.

His first ranking tournament victory came at the 1998 Regal Welsh Open, where he defeated no fewer than seven players to lift the title and claim the £60,000 winner's cheque. Paul Wykes (5-3), Neal Foulds (5-2), Steve Davis (5-3), Nigel Bond (5-4), Alan McManus (5-3) and Peter Ebdon (6-1) all fell at the hands of the 19-year-old, before he overcame World Champion to be John Higgins 9-5 in the final. During the final, Hunter made three century breaks (108, 116 and 127). He followed up that success by reaching the semi-finals of the 1998 Liverpool Victoria UK Championship in Bournemouth and was named the Snooker Writers Association's Young Player of the Year for that year.

Hunter's first appearance at the Crucible came in 1999 World Championship, where he lost 8-10 in the first round to the eventual champion Stephen Hendry. His form that season elevated him to no. 12 in the 1999/2000 world rankings resulting in automatic qualification into the final stages of ranking tournaments for the first time.

In the 2001 Benson & Hedges Masters, Hunter beat his close friend and defending champion Matthew Stevens 6-5 in the last 16, Peter Ebdon 6-3 in the quarter-finals and Stephen Hendry 6-4 in the semi-finals before recovering from a 7-3 deficit against Fergal O'Brien to win the final 10-9. The match turned on the pivotal eleventh frame, where Hunter looked like trailing 8-3 but recovered to reduce his deficit to 7-4, before knocking in four centuries in six frames on his way to a famous 10-9 victory.

After his best ever season, in which he had been a contender in virtually every tournament he played, it was time for the Yorkshireman to perform in the biggest tournament of all, and that he most certainly did. In the 2003 Embassy World Championship, he beat Allister Carter 10-5, Matthew Stevens 13-6 and defending champion Peter Ebdon 13-12 in an epic encounter to reach the semi-finals.

In the last four, he established a 15-9 overnight lead over Ken Doherty by playing some of the best snooker of the tournament. It was only an inspired Doherty comeback, winning eight of the remaining nine frames, that would deny him a place in his first Crucible final. The 2002/2003 campaign was still his most consistent, winning one title, reaching a further four semi-finals and three quarter-finals. It earned him a place in the world's top eight in the 2003/2004 world rankings for the first time in his career, having been ranked number nine for the previous two seasons.

In 2003/2004, his biggest achievement of another successful season was winning the Masters, for the third time in four years, yet again by a 10-9 scoreline. The 2004 final was arguably the most dramatic of all his Masters triumphs, trailing Ronnie O'sullivanthroughout the entire match before pipping him to the trophy in the final frame. In fact, Hunter trailed 2-0, 6-1, 7-2, 8-6 and 9-7 before reeling off the final three frames to seal the sixth title of his professional career.

Hunter and Lindsey Fell, a beauty therapist, married in the summer of 2004 in Jamaica. On 26 December 2005, Lindsey gave birth to their first and only child, daughter Evie Rose.

On 6 April 2005, Hunter announced that he was suffering from malignant neuroendocrine tumours , for which the causes are unknown. A spokesman for the World Professional Billiards and Snooker Association said at the time: "Paul will undergo treatment to cure himself of this illness. He would like to reassure his fans and supporters that, as with his snooker career, he is tenacious and positive in his fight against the disease."

It is believed that Hunter's treatment was of limited success and that he was often in some pain. On 27 July 2006, the WPBSA confirmed that, following a members' vote, the organisation's rules would be changed to allow Hunter to sit out the entire 06/07 season with his world ranking frozen at 34. He intended to devote the year to treatment for his cancer.

Hunter died on October 9, 2006 – just five days short of his 28th birthday – at the Kirkwood Hospice in Huddersfield. His funeral took place on October 19, 2006. Following his death, thousands of tributes poured in from some of the most famous names in snooker.