An international at U16 and U18 level, Gentile was named to the All-Tournament Team after helping Italy to silver at the 2011 U20 European Championship in Bilbao, four months after making his senior debut against a Serie A All-Star side. His competitive bow came at EuroBasket 2013. After starting out at Treviso, he moved to Milano in 2011 where he won the Italian league title and MVP award in 2014 and is now the team captain. He was selected by the Minnesota Timberwolves with the 53rd pick in the 2014 NBA Draft but his rights are now held by the Houston Rockets. He is the youngest son of Nando Gentile, who won the Euroleague with Panathinaikos, while elder brother Stefano, also an Italian international, plays for Reggio Emilia. Engaged to Isabella, a Brazilian model, he is an avid video gamer.