Khan was born and raised in Bolton, England and is an avid supporter of his local football club, Bolton Wanderers, where he uses the club's training facilities at the Reebok Stadium.

Khan belongs to the Janjua Rajput clan of Maira Matore in Rawalpindi, Pakistan, which has a long and well documented history of warrior kings and a strong martial reputation.

He was educated at Smithills School in Bolton and Bolton Community College. His first cousin is the England fast bowler Sajid Mahmood and his younger brother, Haroon Khan, is an amateur boxer. He was a hyperactive child and "a born fighter", according to his father, who encouraged him to take up boxing.

He often uses his position as a well-known British Muslim to encourage better relations between British Muslims and the wider community, particularly in his home town of Bolton.

Amateur

Khan began boxing competitively at the age of 11, with early honours including three English school titles, three junior ABA titles and gold at the 2003 Junior Olympics. In early 2004 he won a gold medal at the European Student Championships in Lithuania, and in South Korea several months later he won world junior lightweight title after fighting five times in seven days. Khan then rose to fame as Britain's sole representative in boxing at the 2004 Athens Olympics, winning a silver medal at the age of 17 in the lightweight boxing category. He was Britain's youngest Olympic boxer since Colin Jones in 1976. He lost in the final to Mario Kindelan, the Cuban who had also beaten him several months earlier in the pre-Olympic match-ups in Greece. In 2005 he avenged the two losses by beating the 34 year old Kindelan in his final amateur fight.

Olympic results

Round of 32: Defeated Marios Kaperonis of Greece (RSC-3)
Round of 16: Defeated Dimitar Stilianov of Bulgaria (37-21)
Quarterfinals: Defeated Jong Sub Baik of South Korea (RSC-1)
Semifinals: Defeated Serik Yeleuov of Kazakhstan (40-26)
Gold Medal Match: Lost to Mario Kindelan of Cuba (23-30)

Professional 2005–2006

Despite declaring after the 2004 Olympics that he would pursue a Gold medal at the 2008 Beijing Olympics, Khan turned professional in 2005, signing with England's leading boxing promoter, Frank Warren. This was fuelled by a row with the English Amateur Boxing Association over the ticketing allocation for his family and friends at the English ABA Finals.

Khan moved from Lightweight to Light Welterweight for a single fight against French fighter Rachid Drilzane on December 9, 2006, winning a 10 round decision. Khan experienced the first knockdown of his career; he got his foot caught in the rope and touched down with his glove, giving the referee no choice but to award his opponent the knock-down. Drilzane had never scored a knockout in his 13 fight career. Khan did not defend this belt — instead he returned to the Lightweight division for future fights.

Khan announced his intention to be a World Champion by the time he was 21, by the end of 2007 — an ambition that was not to be fulfilled. His comments prompted reactions from boxing fans directed towards his promoter to increase the level of his opposition.

2007

On April 7, 2007, Khan beat Steffy Bull in a three round technical knockout in Cardiff.

On July 14, 2007 he faced Willie Limond for the Commonwealth lightweight title. During the fight Khan was knocked down in the 6th round and appeared to be hurt badly. However, after another barrage of right hands, Khan weathered the storm and in the seventh round knocked down Limond after a fierce exchange of punches. The referee stopped the fight on advice of the doctor; Limond had sustained a perforated eardrum, broken nose and damaged right eye.

On October 6, 2007 Khan faced Scott Lawton in his first defence of the Commonwealth Lightweight Title. Khan fought a mature and clinical fight, boxing with single punches for the majority of the first three rounds. Khan increased the pressure at the end of the third, and secured a TKO victory in the fourth. The referee stepped in when Lawton failed to fight back.

The most significant win of Khan's career so far came when he celebrated his 21st birthday by successfully defending his Commonwealth Lightweight Title against Graham Earl on December 8, 2007. Earl, rated the number one British lightweight and a former world title challenger, was considered Khan's toughest test by some way and a tough fight was expected; especially due to some ill-feeling between the pair in the run-up to the fight. However, it took Khan just 72 seconds to have the fight referee declare Earl in no fit state to continue. The speed with which Amir dispatched his man came as a big surprise to most observers, Earl looking barely in the same ring as the Commonwealth champion. Khan later claimed that he rated this victory as the best of his career.

2008

On February 2, 2008, Khan was scheduled to fight Martin Kristjansen but illness forced the Dane to withdraw and instead Khan beat Australian Gairy St Clair in a contest for the Commonwealth lightweight title at the ExCel Arena in London. This was his first fight to last all 12 rounds and was won via a unanimous 120-108 scoring from all three ringside judges.

On April 5th 2008, Khan beat Kristjansen in the 7th round of a WBO World Lightweight title eliminator. Despite being warned for hitting Kristjansen after he had dropped to the floor towards the end of the seventh, a further onslaught by the British lightweight forced the referee to stop the fight as the Dane was unable to defend himself. Before the contest, the fighters had been ranked 3rd and 4th respectively by the WBO. After Khan's victory, he is now ranked 2nd, behind only Joel Casamayor.

Khan is set for a bout on June 21, 2008 at the National Indoor Arena in Birmingham against Irishman Michael Gomez. The fight against Gomez, a super featherweight who is reaching the end of his career and has lost the last three of his six fights, has been described as a "backward step" in Khan's quest for a world title. Khan himself has stated "I think I'm above this domestic level now" and expects a fast and explosive finish to the fight.

In April 2008 Khan split from his trainer Oliver Harrison, the trainer for all of his previous 17 professional contests. The breakup has been blamed on Harrison's concerns that Khan's public engagements were interfering with his fight preparations. An official spokesperson for Team Khan told reporters there was nothing personal between Khan and Harrison. Dean Powell, who has trained former world champions Duke McKenzie and Lloyd Honeyghan, will work with Khan until his next fight at Birmingham's National Indoor Arena on June 21. A decision on a permanent trainer will be taken afterwards, with Khan possibly looking to America. Khan has recently (April 2008) had a training session in Las Vegas with Roger Mayweather, trainer and uncle of Floyd Mayweather.