Mansour Gueye was born on 30 December 1985 in Dakar, Senegal, leaving the country to go to Switzerland in 1999 at age 14, signing with Servette.[3][4][5][6] He played mainly at the youth center, in his last season being promoted to the satellite team.[3]
In 2004 he got transferred in Romania at Politehnica Timișoara, making his Divizia A debut on 11 August under caretaker coachCălin Zanc who sent him in the 80th minute in order to replace Cristian Silvășan in a 2–1 away loss in front of FCM Bacău.[3][7] In the following game, he was used by new coach Gheorghe Mulțescu as a starter, scoring his first two goals in a 2–1 home win over FC Brașov.[3][8][9] Afterwards he scored three goals against each of the Bucharest giants, Rapid, Dinamo and Steaua, the one against Dinamo being from a scissors kick which left goalkeeperBogdan Stelea without a reaction.[10] By the end of the season he scored the only goal of a 1–0 home victory with Farul Constanța and in the final round of the season he opened the score after a superb combination with Viorel Moldovan in a 2–1 loss on the Ghencea Stadium with the eventual champions, Steaua, thus having a total of 7 goals scored in the 2004–05 season.[3][11] The following season, Mansour was coached by Gheorghe Hagi for a while, scoring only two goals in two wins over Politehnica Iași and FCM Bacău.[3][12] Next season he helped the team reach the 2007 Cupa României final where coach Valentin Velcea used him in the first 55 minutes of the 2–0 loss in front of Rapid.[3][13] In the 2007–08 season, Mansour scored only one goal in the league but it was a spectacular one, with a scissors kick after a counter-attack in a 2–0 with Steaua.[3][14]
Mansour started the 2008–09 season, playing for Liga II club, CS Buftea, being loaned there by Politehnica, showing an appetite for goal as he scored 8 times in the first half of the season.[3][15] For the second half, he returned to first league football, Politehnica loaning him this time at Gloria Buzău where he scored seven goals, of which five were in the last four matches of the season, one in a draw Universitatea Craiova, two in a victory over Vaslui, one in a 1–1 with Politehnica Iași and the final one was in a 2–1 win with Gloria Bistrița, these performances helping his side avoid relegation.[3][16]
In the summer of 2009 he returned to Timișoara but in a friendly with Debrecen from July he suffered an injury which kept him off the field for the whole first half of the season, making only six appearances in the second one, scoring two goals in a 6–0 win over Unirea Alba Iulia and opening the score in a 1–1 with Ceahlăul Piatra Neamț.[3][17] In the following season, Mansour made his debut in European competitions, coach Vladimir Petrović sending him on the field in the 72nd minute in order to replace Lukáš Magera in a 3–3 with MyPa from the second leg from the third qualifying round of the 2010–11 Europa League, helping Politehnica advance to the play-offs where they were eliminated by Manchester City without him playing.[18] On 22 September 2010 he scored one goal in a 3–1 victory from the Cupa României against second league side, Juventus București, but in the same match he suffered another serious injury which kept him off the field for a long period of time.[19]
During his years spent at Politehnica, Mansour Gueye had offers from Premier League side Newcastle United and Bundesliga's Werder Bremen, also from Bucharest teams, Rapid, Dinamo and Steaua but because of his injuries or failed negotiations, the transfers were never made.[5][20]
For the second half of the 2013–14 Liga I season, Mansour returned to Timișoara at ACS Poli, but the spell was unsuccessful as the team relegated at the end of the season with him making only five league appearances, having a total of 101 matches with 24 goals scored in the competition.[3][24]
Mansour has three brothers and four sisters, two of his brothers were also footballers: Azis played at junior level in Italy for Fiorentina, Juventus and A.S. Roma and Ousmane played mostly for clubs in the Romanian lower leagues.[4] In 2008 he married Adelina Ziele but got divorced after a few months.[29] Around 2010 he met Ramona Popa who gave birth about one year later to his first child, Mouhamed.[30]
^"Scandal - Bataie la Steaua!" [Scandal - Fight at Steaua!] (in Romanian). Jurnalul.ro. 18 May 2005. Retrieved 26 December 2023. "Steaua e campioana Romaniei" [Steaua is the champion of Romania] (in Romanian). Hotnews.ro. 11 June 2005. Retrieved 31 December 2023.
^"Ea este viitoarea sotie a lui Gueye Mansour" [She is the future wife of Gueye Mansour] (in Romanian). Libertatea.ro. 7 December 2007. Retrieved 2 January 2024. "Adelina lui Mansour" [Mansour's Adeline] (in Romanian). Gsp.ro. 12 December 2007. Retrieved 2 January 2024. "Mansour a divortat" [Mansour has divorced] (in Romanian). Mediafax.ro. 9 April 2008. Retrieved 29 October 2020.