Nadir Belhadj was born in Saint-Claude in France, and started out at RC Lens at left back, a position where he could make full use of his natural attacking capabilities. Unable to break into the first team for Les Sang et Or, he went out on loan to Gueugnon in 2002, and the board of directors at Les Forgerons were so impressed they decided to take up their option to buy the player after just 26 matches in Ligue 2. In 2004, he moved to Sedan, and he helped Les Sangliers back in the top flight of French football two years later. In January 2007, he signed a contract to move to Olympique Lyonnais.
He saw out the rest of the season at Sedan as part of the deal, but when he finally joined up with his team-mates at OL, Alain Perrin saw Fabio Grosso as a better option in the left back berth. As a result, Belhadj only featured nine times, and in the end, thought it better to leave the club mid-season. So it was that in January 2008, Belhadj went back to his first club, Lens. Unable to prevent the northern club from escaping relegation, he was forced to find another port of call and in September 2008, he went out on loan to Portsmouth for a year. An impressive start in the Premier League convinced the Pompey bosses to bring him to the club on a permanent basis. During his time in England, he has had the opportunity to sample European competition, notably in the impressive 2-0 victory over Portuguese side Vitoria Setubal. In that same season, the south coast club shared the spoils in a heart-stopping encounter with AC Milan, with Belhadj putting in one of his most accomplished performances for the club and earning the man of the match award.
Belhadj was called up for Algeria for the first time in 2004 for an unofficial friendly against the Belgian outfit La Louviere, and one month later played against China. But it was his performance against Argentina in a June 2007 friendly at Barcelona's Nou Camp stadium that made the biggest impression in Algeria. Les Fennecs finally went down 4-3, but Belhadj had a great game, scoring two of the goals. Belhadj has skill in abundance and likes nothing better than to charge forward down his left flank. With the likes of Barcelona and Roma reportedly interested in securing his services, he will be anxious to shine in South Africa, after serving a suspension for Algeria's opening match against Slovenia.