Mario Kasun was born in Croatia on April 5, 1980 and he is 213 centimeters tall.
He made his debut with KK Gorica, in the Croatian 2nd Division, during the 1997-98 season. Later he signed for the 1998-99 by KK Zrinjevac and played there till the 2000-01 championship. Moved to Germany for the 2001-02 season, signed by Cologne 99ers and he has been released on January '02. Signed for the 2002-03 season by Frankfurt Skyliners and he played there also the 2003-04 championship. Signed for the 2004-05 season by Orlando Magic and he stayed in Orlando also for season 2005-06. Then he moved to Spain for the 2006-07 and 2007/08 seasons, signed by FC Barcelona. For the 2008-09 and 2009/2010 seasons, he played for Efes Pilsen Istanbul and after that he moved to Crotia for the 2010-11 season, signed by KK Zagreb, the team in which he played also the season 2011/2012, in which he finished the Euroleague season with 12.2 ppg and 6.6 rebs.