Hamed was born in Sheffield, Yorkshire, England to Yemeni parents, in 1974. A protege of Brendan Ingle’s Wincobank gym, his talent and flashy southpaw style marked him out from an early age.

Hamed started boxing professionally at flyweight in 1992. He soon began rising through the ranks as he knocked out a series of opponents in the opening rounds. Age 20 he won the European bantamweight title, comprehensively beating the beleaguered Vincenzo Belcastro over twelve rounds. After one defence he won the WBC International super bantamweight title in 1994, overwhelming Freddy Cruz in Sheffield, whom he severely punished and stopped in six rounds. Hamed’s popularity grew, his unorthodox style winning a large fan base and his boxing antics generating a large group of detractors. After signing for Frank Warren, Hamed, employing more spectacular entrances, knocked out better opposition in Enrique Angeles and Juan Polo Pérez, both within two rounds.

Later in 1995, after controversially being named the WBO #1 featherweight contender (despite never having boxed at that weight), Hamed moved up to face Wales’ defending WBO champion Steve Robinson. After dominating the bout and scoring a knockdown in round 5, Hamed won the title when the referee stopped the fight in round 8 after Robinson was caught with a left hook that dropped him spectacularly. The fight was held in front of Robinson’s home crowd at the rugby ground, Cardiff Arms Park, with rain pouring down on the fighters and the ring. This was also the first bout where Hamed badly injured his hand, a problem that would continue for the rest of his career.

Hamed was referenced by hip-hop artist Nas in the song “You Won’t See Me Tonight”, with the lyrics “I can’t forget how I met you, you thought I was a boxer/ Prince Naseem, but I’m a mobster, Nas from Queens”. Hamed himself recorded a song with hip hop group Kaliphz called “Walk Like a Champion”, which reached number 23 in the UK Singles Chart in 1996.

In February 1997, Hamed defeated long-time IBF champion Tom “Boom Boom” Johnson in eight rounds in a unification bout at the London Arena. After being constantly stunned and staggered from round 3 onwards, Johnson was finally dropped by a huge uppercut, then saved from further punishment by the referee. Hamed’s first defence of both the WBO & IBF titles was a first-round KO of veteran British boxer and European champion Billy Hardy. Before the bout Hamed had correctly predicted he would win in round 1. The next defence was an easy two-round win against a hugely outclassed Juan Gerardo Cabrera. Due to boxing politics involving the IBF’s mandatory challenger, Hamed was soon forced to relinquish the IBF title.

In Hamed’s hometown of Sheffield in October 1997, he produced one of the best performances of his career in defending his WBO title against Jose Badillo, whose corner entered the ring to stop the fight during round 7. Hamed’s status as one of the biggest draws in the sport was evident with a stellar undercard that included Joe Calzaghe vs. Chris Eubank for the world super middleweight title.

In late 1997 Hamed made his heavily hyped U.S. debut. His ceremonious arrival on the British Airways Concorde was covered by multiple media outlets. There, he and former WBC title holder Kevin Kelley fought in a highly entertaining bout at New York’s Madison Square Garden. Prior to the fight, Kelley told Hamed, “I’m gonna smoke your boots”. This fight marks something of a watershed in Hamed’s career, as he was forced, for the first time, to abandon his hands-down style of fighting throughout the entire course of the bout, given the calibre of Kelley. Nonetheless, despite suffering three knockdowns himself, Hamed put Kelley down for a third and final time to win by a fourth-round knockout. This was his first of many fights on HBO.

By 1997, Hamed had an annual income of $14 million (£8,548,914) from fight purses and endorsements, ranking at number-22 on Forbes’ list of the world’s highest-paid athletes for 1997. By March 1999, his net worth was an estimated £38 million. By January 2001, Hamed had reportedly amassed a fortune of £50 million ($75,746,700). He earned over $48.5 million from fight purses, including $8.5 million from his fight against Barrera. Hamed was the second richest British boxer, after heavyweight champion Lennox Lewis in 2003.

In 1998, Hamed enjoyed victories over former three-time WBA title holder and then-lineal champion Wilfredo Vazquez (TKO 7), former WBC bantamweight title holder Wayne McCullough (W 12), and future IBF title holder Paul Ingle (TKO 11; no relation to Hamed’s then-former trainer Brendan Ingle).

Hamed also inspired a character called Prince Naseem in the fighting game Ehrgeiz, released in 1998. While called “Prince Naseem” in the original Japanese version, the character’s name was changed to “Prince Doza” in the Western versions.

In October 1999 at Joe Louis Arena, Detroit, Michigan, United States, Hamed defeated WBC featherweight champion Cesar Soto of Mexico over 12 rounds, adding the WBC title to his collection and unified the WBC & WBO titles. Hamed soon chose to relinquish his WBC title due to his commitment to being WBO champion.

In March 2000 at Olympia, Kensington, London, Hamed knocked out former undefeated long-reigning IBF super bantamweight title holder, Vuyani Bungu of South Africa. The fight was ended with a single straight left hand, in one of Hamed’s most impressive performances and biggest victories.

Hamed fought in August 2000 against Augie Sanchez at Foxwoods Resort, Mashantucket, Connecticut, United States. Sanchez is known for being the last American to defeat Floyd Mayweather as an amateur boxer.

Hamed had a licensed sports fighting game, Prince Naseem Boxing, published by Codemasters for the PlayStation console in 2000. A portable version of the game was also released for the Game Boy Color, developed by Virtucraft, which later in 2002 developed a Mike Tyson based follow-up, Mike Tyson Boxing, for the Game Boy Advance.

Eight weeks prior to the fight, which took place at the MGM Grand Garden Arena in Las Vegas on 7 April 2001, Marco Antonio Barrera prepared to fight. Barrera had moved up a weight division. At the end of training camp he was in the best shape of his life. According to Sky Sports, Barrera had “trained like a monk” in Big Bear, California, while Hamed trained in Bing Crosby’s old house. Emanuel Steward had arrived to oversee the last two weeks of Hamed’s training, including sparring, and was worried immediately. He had seen Barrera look razor sharp only a few months before in a stoppage win in Las Vegas, and watched Hamed not take his sparring with young Mexicans seriously. The fight was also for the International Boxing Organization World featherweight title.

On 18 May 2002 at London Arena, Docklands, London, Hamed returned to the ring for what turned out to be his final boxing match, against the European champion Manuel Calvo (33 wins, 4 losses, 1 draw) for the IBO World featherweight title. Hamed was booed by the 10,000 fans as he won unconvincingly on points after 12 rounds looking sluggish and uninterested. The judges scored the fight 120-110 and 119-109 (twice). In a post-fight interview with Ian Darke, Hamed assured a quick return to the ring, which ultimately never happened. Hamed was just 28 years old when he stopped fighting. For years, Hamed did not confirm whether he had retired or not; there were talks of several fights in the UK and in the US, including Hamed’s brother and manager, Riath, speaking to HBO about a potential fight with Michael Brodie.

As popular lower weight fighters like Oscar De La Hoya and Kostya Tszyu moved into the mid-weight classes and the Mexican champion Julio César Chávez declined, Hamed and Arturo Gatti filled the void. Hamed’s boxing antics made him the new poster-boy for lighter-weight boxers and his charisma attracted a large number of fans. In 2002 the UK public voted Hamed’s victory over Kevin Kelley on the list of the 100 Greatest Sporting Moments.

Naseem Hamed held the pay-per-view record in the United Kingdom up until he was surpassed by Lennox Lewis vs. Mike Tyson in 2002.

On 2 May 2005, Hamed was involved in a 90 mph three-car collision at Ringinglow Road in his home city Sheffield, while driving his £300,000 silver McLaren-Mercedes SLR. He was arrested on 3 May, released on bail and later charged at Sheffield Magistrates Court on 3 December. On 31 March 2006, Hamed entered a plea of guilty and was warned he could face jail by a judge at Sheffield Crown Court. The Recorder of Sheffield, Judge Alan Goldsack, adjourned the case until 12 May to allow pre-sentence reports to be prepared. The court heard how the man in the car Hamed hit, 38-year-old Anthony Burgin, who had attended a number of previous hearings, was unable to come to court because he was in hospital for further treatment. His wife Clare was also injured. On 12 May, the court heard in a sentencing hearing how Hamed had been anxious to impress businessman Asif Ayub, who was a passenger in his car. Hamed crossed a solid white line at a speed of at least 90 mph and crashed head-on into a Volkswagen Golf that emerged from a dip in the road. Hamed’s car then hit a second vehicle, the Ford Mondeo he had been trying to overtake. Mr. Burgin, the driver of the Volkswagen Golf, was very seriously injured, breaking every major bone in his body and suffering bruising to the brain. Hamed escaped unhurt.

Hamed was jailed for 15 months after pleading guilty at an earlier hearing. He was also given a four-year driving ban. Judge Alan Goldsack told Hamed: “I find it astonishing that the DVLA has not been prepared to cooperate with the prosecution to give them details of your earlier offences – apparently on human rights grounds.” The DVLA’s decision led to Hamed being sentenced without the judge being told he had previously been banned for a year for driving a Porsche at 110 mph on the M1 in Derbyshire. It was also revealed that Hamed had three other previous convictions for speeding offences, details of which the prosecution had to find from court records. Hamed was granted an early release and left prison on 4 September 2006 after serving 16 weeks of the 15-month sentence. Hamed was placed under Home Detention Curfew for the remainder of his sentence, and monitored by an electronic tag. Anthony Burgin, the driver with whom Hamed collided, said: “I am shocked that after such a serious accident Mr Hamed has been released after less than four months.” After a recommendation from the Honours Forfeiture Committee, Hamed was later stripped of his MBE, annulled as a consequence of the conviction. There was also a civil court case rumoured to cost Hamed up to £1 million plus legal costs, as Burgin was deemed unable ever to work again. Burgin was later arrested and charged with dangerous driving for an incident alleged to have involved Eleasha Hamed (the wife of Naseem) on 19 April 2007. Burgin pleaded not guilty, and appeared in court on 17 March 2008, following which he was cleared of charges.

British boxing pundit Steve Bunce stated on 15 March 2008 edition of BBC panel show Fighting Talk that Hamed was the greatest British boxer of all time. World Boxing, a sister publication of The Ring magazine, ranked Hamed the 11th greatest British boxer of all-time, while Gareth A. Davies, boxing correspondent of The Telegraph ranked him 10th. The Ring also ranked Hamed the 46th greatest puncher of all-time.

Hamed was part of the 2015 class for the International Boxing Hall of Fame. In 2016, ESPN ranked Hamed at number 22 on its list of the top 25 pound-for-pound fighters of the last 25 years.