An autopsy will be completed, with Cronin reportedly suffering a suspected heart attack.
“I came to Canberra around the same time as him and out of sheer luck I got to be roomed up with him back in 2013,” former Raider Jordan Rapana told Fox Sports.
“He was just an all-round top bloke; I just want Australia and the world to know how good of a bloke Mitch is.
“He just had that effect on everyone … he’s one of them guys that’s everybody’s best mate, has that positive aura and you want to be around him.”
QRL competitions manager Dave Maiden said Cronin was an outstanding person and leader who inspired those around him.
“Mitchell was a fantastic leader of men and a quality player,” Maiden said.
“More importantly though, he was a quality human being who will be mourned by many and missed by all.
“The people who came across him will be in state of disbelief … he’s one of the good ones.”
Seagulls chief executive Hanan Laban described him as a quiet achiever who was fearless on the field, yet humble and modest.
“We are devastated by the passing of our captain Mitch Cronin and we send out love to Chris, Andrea, Ben, Amy and the Cronin family,” Laban said.
“Mitch was an exceptional young man who was loved and respected by his teammates, his coaching staff, our supporters and the wider rugby league community.
“From the moment he arrived at Wynnum he embodied the values of the Seagulls through his positive attitude, strong work ethic, and deep care for his teammates and his club.”