The New Zealander was a salesperson for Ray White New Farm and also worked as a personal trainer at Orangetheory Fitness Ascot.
He was raised in New Zealand and lived in Auckland prior to his move to Brisbane.
Colleagues at the fitness centre have told media his death is still "raw" and no one feels ready to talk about it.
The team at his real estate job say they are "absolutely devastated and incredibly saddened".
Ray White New Farm principal Haesley Cush said he was "well loved by everyone" and "a genuinely all-round great guy".
"It's a terrible tragedy," he added.
"He was just so kind and caring, and people told him that regularly.
"Our thoughts and prayers are with Matty's family and friends and we want them to know they have the full support of the Ray White group moving forward."
King had a passion for travelling. "Life's not meant to be lived in one place," he wrote on his Instagram bio.