After beginning his career with the Le Havre youth team, Niang turned professional at 18 years of age with Troyes.

Jean Fernandez, the Metz manager, tried to make the loan deal into a permanent move but failed and Niang left Troyes for Strasbourg.

The 2004–05 season saw Mickaël Pagis arrive at Strasbourg, and a fruitful new partnership was formed, with the pair linking up for 27 goals in the league.

[7] On 19 October 2011, at the 2011 AFC Champions League semi-final match against Suwon Samsung Bluewings, he scored the controversial, un-sportsmanlike second goal for his team.

After all, AFC did not conclude this issue justly, by giving disciplinary actions to Suwon only, Al Sadd getting absolutely nothing, not even Niang or Keita.

[8] He then got himself sent-off in injury time for kicking the ball away when he was flagged offside, receiving another yellow card in addition to his previous, meaning he could not participate in the second leg in Doha.

[10] On 3 March 2013, he scored his first goal and contributed with an assist in a 3–2 win against his old club Fenerbahçe securing 3 points for his team in the final derby ever on İnönü Stadium.