Sow played his first game for RC Lens on 22 May 2009, the season Lens won Ligue 2.[1] He scored his first goal for the club on 15 May 2010 in the 36th minute against Bordeaux, which they won 4–3. He scored in the 95th minute to make the score 3–0 in the Coupe de la Ligue 1st round against Clermont on 22 July 2011.
On 1 August 2019, Sow signed for EFL Championship side Nottingham Forest on a two-year deal.[4] Sow was a key player for Forest during the 2019–20 season. Notability, Forest had a win rate of 52% when Sow was in the team, compared to 30% when he was not playing.[5] He featured less regularly during his second season at Forest due to a recurring injury problem, and was released following the end of his contract on 1 June 2021.[6]
International career
Sow played his first game for Mali on 27 December 2009, against North Korea in a 1–0 defeat for Mali.[7]