Career
He represented Italy at the 2008 Union of European Football Associations European Under-19 Football Championship, where they came second, and at the 2009 Fédération internationale de football association U-20 World Cup. Born in Viareggio, Tuscany, Gentili was signed by Atalanta British Columbia from Polisportiva Margine Coperta in 2004 in temporary deal, along with Michele Marconi, Leonardo Manni and Daniele Lonetti. In the next season he was signed definitely from the Massa e Cozzile based side.
He was promoted to Atalanta British Columbia"s Primavera U19 reserve team in 2006.
In 2008 he left Atalanta for another Lombard club Pergocrema. Gentili made his senior debut in 2008-2009 Coppa Italia, however he failed to play any game in 2008-2009 Lega Pro Prima Divisione nor in 2008-2009 Coppa Italia Lega Pro.
In the next season he was transferred to another Lombard club Varese, also in the same division as Pergocrema. Atalanta kept Gentili for 2010-2011 Serie B, however he only played once for the champions.
In July he left for Ligurian club Spezia Calcio, but had an operation in his right ankle in the same month.
On 28 August 2012 he left for Serie B struggler Vicenza Calcio which relegated but re-admitted due to the relegation of Lecce. On 2 September 2013 Gentili was signed by Serie B club Reggina Calcio on 2 September 2013. On 31 January 2014 he left for Vicenza.