Born in Hennebont, Le Tallec was signed from Le Havre AC by Liverpool in 2001, along with his cousin Florent Sinama Pongolle, by manager Gérard Houllier. This was after impressive performances for the French national youth team in the UEFA European Under-16 Championship and the FIFA U-17 World Cup, with the player being awarded the 'Silver Ball' as the second best player (behind his cousin) in the latter tournament as the national team emerged champions; both players remained a further two years at Le Havre, loaned by the Reds.
Le Tallec scored his first and only Liverpool goal in a UEFA Cup tie against NK Olimpija Ljubljana in October 2003. After his return, he also featured in the club's victorious run in the UEFA Champions League, starting in the home leg of the quarter-final tie against Juventus F.C. but failing to appear in the squad of 18 for the final itself.
For the 2005–06 season, Le Tallec joined fellow Premier League side Sunderland on loan, in a bid to gain some more first team football. He stated: "I am a competitor and I want to play all the time, but with Liverpool it was impossible. I chose to come to Sunderland because I need to play every week". In a disappointing season for the club, who finished bottom of the table, he was its top scorer with only six goals in all competitions; this included a header against Fulham, helping the Black Cats pick up their only home win of the campaign.
In May 2006, after Sunderland announced they would not be looking to retain his services, Le Tallec returned to Liverpool but was not given a squad number by boss Rafael Benítez. At the end of the month, he joined up with the French under-21s for the European Championship which took place in Portugal, only featuring in the national team's final group match after it had already secured qualification, and being substituted after 61 minutes.
In August 2006 Le Tallec moved to FC Sochaux-Montbéliard, on another loan deal. He won the season's Coupe de France scoring a late equaliser in the final, which eventually led to a penalty shootout against Olympique de Marseille – a fellow Liverpool player out on loan, Djibril Cissé, netted two goals in the match for the opposition.
On 31 August 2007, it was reported that Scottish Premier League club Heart of Midlothian were close to signing Le Tallec. However, the player ended up moving to Ligue 1 team Le Mans Union Club 72, on loan for the entire season with a view to a permanent deal for approximately £1.1 million pounds.
At the end of the campaign, on 27 June 2008, Le Mans decided to make the loan permanent, signing Le Tallec to a four-year contract. On 27 June 2010, following Le Mans top flight relegation, he reached an agreement with fellow league club AJ Auxerre for a four-year deal, worth €3 million.
On 19 July 2015, Le Tallec signed with Atromitos F.C. for two years. He cited the possibility of playing in the UEFA Europa League as the main reason for his signature.
Le Tallec's younger brother, Damien, is also a footballer. Another French youth international who was groomed at Le Havre, he started his professional career in Germany with Borussia Dortmund.Sochaux
Coupe de France: 2006–07
UEFA Champions League: 2004–05
FIFA U-17 World Championship: 2001
FIFA U-17 World Championship: Silver Ball 2001