Mario Delaš made his professional debut in KK Split, during the 2006–07 season. In January 2010, he signed a contract with BC Žalgiris for the next 3+1⁄2 seasons.[2] During the 2010–11 season, he was loaned to KK Cibona[3] and BC Šiauliai. He spent most of the 2011–12 season on loan in the Žalgiris subsidiary BC Baltai, returning to the Žalgiris team in March 2013. He signed with Obradoiro CAB in the summer of 2013.[4] On June 30, 2014, he signed a multi-year deal with Cedevita Zagreb.[5] In the first days of 2016, after spending the first half of the 2015–16 season in Cedevita, without playing a single minute, he moved to the Estonian side Kalev/Cramo for the rest of the season.[6] On September 19, 2016, he signed with the Italian Serie A club Orlandina Basket.[7] On February 14, 2018, he parted ways with Orlandina.[8] Two days later, he signed with Pallacanestro Varese for the remainder of the season.[9]
Delaš represented his country's junior national teams in Under-16, Under-18, Under-19 and Under-20 competitions, winning bronze medals at the 2008 FIBA Europe Under-18 Championship, and at the 2009 FIBA Under-19 World Cup. He was selected to the All-Tournament Teams of both championships, and also won the MVP award in the latter tournament, averaging 20 points per game. His first call-up to the senior men's Croatian national basketball team came in 2013. He was a part of the Croatian team that took 4th place at the 2013 EuroBasket, where he played only a minor role in his team's success.
