Haggui made his Ligue 1 debut in Strasbourg's first game of the 2004–05 season, a 2–1 away defeat at SC Bastia on 7 August 2004, coming on as a substitute.

He started his second season with Strasbourg as a regular, scoring his only two Ligue 1 goals with a brace in the club's 4–2 defeat at home to Toulouse on 24 September 2005.

He also appeared in six UEFA Cup matches before Strasbourg were knocked out by Basel in the round of 16, scoring the opening goal in their 5–0 win at home to Grazer AK on 29 September 2005.

He experienced mixed fortunes in his first season with Leverkusen, playing regularly for the majority of the season, but also receiving a total of 11 yellow cards in the league and delivering a couple of poor performances, most notably against Bochum in April 2007, where he was substituted only 23 minutes into the game after being directly responsible for two of Bochum's three goals in the opening 22 minutes.

On 1 June 2009, just two days after the German Cup final, Haggui decided to leave Leverkusen on a free transfer and signed a two-year contract with Bundesliga rivals Hannover 96.

[3] Haggui made his competitive debut for Hannover on 2 August 2009 in their 3–1 defeat at Eintracht Trier in the first round of the German Cup, playing all 90 minutes.

[10] Haggui has been a member of the Tunisian national football team since 2003, making his international debut on 20 August 2003 in their friendly match against Guinea.

In the 2006 FIFA World Cup qualifying, he made a total of seven appearances and scored two goals in Tunisia's opening match of the campaign, a 4–1 win at home to Botswana on 5 June 2004.

At the tournament, Tunisia were knocked out in the quarterfinals after losing 3–2 to Cameroon in extra time, with Haggui forced to leave the pitch with an injury after 38 minutes.