Rennes He started his professional career at
Stade Rennais in 2004 as an 18-year-old. In his first couple of seasons, Sow made his mark mostly in cup competitions, scoring a brace for
Rennes against
Corte on 6 January 2006 in the
Coupe de France and one in an away game against
Lille in the
Coupe de la Ligue.
Sedan (loan) He was loaned out to
Sedan in 2007, scoring six goals in 30 appearances for the club. Upon his return to Rennes, he was the club's first-choice striker for two seasons before joining
Lille on a free transfer In June 2010.
Lille After his contract with
Rennes came to an end, the 24-year–old forward signed a three-year deal with
Lille OSC on 28 June 2010. Sow scored on his debut for Lille in a 1–1 draw away to his former club Rennes. But Moussa Sow did not score again in the league until a 90th-minute goal on 19 September gave Lille all three points in a tough home contest against
Auxerre. Sow scored his first hat-trick for Lille on 13 November 2010, the goals came in a 5–2 away victory to
Caen, with both
Gervinho and
Franck Beria grabbing 90th-minute goals to seal the win. Less than a month later on 5 December 2010, Sow netted another hat-trick this time against
Lorient. His goals helped Lille to a 6–3 win and firmly placed his side into contention for the
Ligue 1 crown. Lille went into the winter break in sole position of first place, as Sow fired in their only goal in a 1–1 draw with
Saint Étienne on 22 December 2010. Sow scored his 22nd goal of the Ligue 1 campaign in a 2–2 draw with
Paris Saint-Germain on 21 May 2011. The result ensured that Lille would secure their first Ligue 1 title since 1954. Sow scored his third hat-trick, on the final day of the season, as Lille tied the knot on their championship season with an emphatic 3–2 victory over former club Rennes. Sow was the top scorer of the
2010–11 season with 25 league goals and also contributed with three assists and been in the Team of the Year.
Fenerbahçe during a match against
Arsenal in 2014 On 27 January 2012,
Fenerbahçe acquired Sow for €10 million. He signed a 4.5-year contract which would have kept him at the club until the end of 2015–16 season. Sow made his debut against local rivals
Beşiktaş on 5 February 2012, scoring a goal in the second minute of
injury time. On 18 March he scored the first goal of the
derby match with a
bicycle kick against
Galatasaray. He continued his good run of form by scoring a late equaliser against
Kayserispor to earn a draw for his team in
quarter-finals of the
Turkish Cup on 12 April 2012, helping his team to reach the semi-finals through a
penalty shoot-out. Sow also scored the second goal for his team against rivals
Trabzonspor on 15 April 2012. Over the course of the
2011–12 season Sow played 12 league matches and scored 7 goals. Sow earned his first trophy with Fener in the
Turkish Cup final on 16 May as the club ripped apart
Bursaspor by a score of 4–0. In the
2012–13 season Sow scored 13 goals in 22 league matches and three goals in
European matches. On 3 March 2013, he scored twice against Beşiktaş followed by a goal each in the following league matches, a 4–1 victory against Bursaspor and a 2–1 win against.
Antalyaspor. On 22 May 2013, he scored the solitary goal as Fenerbahçe defeated Trabzonspor to secure the club's second straight
2012–13 Turkish Cup, consolation for falling short to city rivals Galatasaray in the league campaign. On 21 September 2013, Fenerbahçe were victorious in a 4–0 win against
Elazığspor while Sow completed his first hat-trick for the club during this match. Sow cried after leaving Fenerbahçe and stated that he will forever be only a Fenerbahçe fan.
Al Ahli On 29 August 2015,
Al Ahli acquired Sow for €16 million.
Return to Fenerbahçe on loan On 31 August 2016, Sow wanted to return to Fenerbahçe and returned to Fenerbahçe on a season long loan deal from Al Ahli. In November 2016, Fenerbahçe began selling shirts with Sow's name and number turned upside as tribute to his repeated times of his amazing bicycle kick goals, the latter of whom he scored a hat-trick against. On 8 December 2016, Sow scored another bicycle kick, this time in the
UEFA Europa League in a 1–0 away victory against
Feyenoord.
Bursaspor (loan) In January 2018, Sow joined
Bursaspor on loan from Al Ahli until the end of 2017–18 season.
Gazişehir Gaziantep On 28 January 2019, Sow signed for
Gazişehir Gaziantep on a one-and-a-half-year contract. ==International career==