|Date of birth||22 August 1988|
|Place of birth||Cagliari, Italy|
|Height||1.77 m (5 ft 10 in)|
|2008–2009||→ Rimini (loan)||5||(0)|
|2009–2010||→ Empoli (loan)||7||(0)|
|2011–2012||→ Siracusa (loan)||1||(0)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 5 March 2017.
‡ National team caps and goals correct as of 14 August 2010
Born in Cagliari, Sardinia, Mancosu started his career with hometown club Cagliari Calcio and made his first team debut in the last round of 2006–07 season, also scoring a goal in his first top-flight appearance, and then made 10 first team appearances in the following 2007–08 season.
On August 13, 2010, it was confirmed that Mancosu was sold to Lega Pro Prima Divisione side U.S. Siracusa, on a co-ownership deal. The Sicilian club, recently underwent a second consecutive promotion from the Serie D in 2008 to the Lega Pro Prima Divisione this season.
In June 2011, Cagliari bought back Mancosu from the co-owner.
In August 2011, he returned to Siracusa on a season-long loan deal. Mancosu was a key person for Siracusa successful campaign which was the first before the winter break.
In 2012, he moved to Benevento, where he spent two years.
In 2014, he was signed by Casertana, where he spent two seasons.
In July 2016 he joined Lecce.
On 12 August 2009 he made his debut with the Italy under-21 team in a friendly game against Russia. Mancosu played all 5 matches of 2005 UEFA European Under-17 Football Championship and all 3 matches of 2005 FIFA U-17 World Championship.
- "Mancosu al Rimini. Rescisso il contratto di Shala" (in Italian). Cagliari Calcio. 2008-07-10. Retrieved 2008-07-13.
- "Marco Mancosu". Sky Sports. Retrieved 2009-08-18.
- Massimo Leotta (2 March 2012). "La Mancosu story Così tre fratelli si sfidano nei gol" (in Italian). La Gazzetta dello Sport. Retrieved 4 March 2017.