The decision said the new venture was "very successful" and Mr Keirsey worked long hours between December 6 and January 3, 2014, when he was sacked.
During that period, the chef worked 12-hour days, which took their toll.
"In these circumstances one might expect some sympathy from an employer when, on two occasions, he slept through his alarm after working late the night before," Mr Wood said.
"Mr Hussein was becoming more and more frustrated with what he saw as Mr Keirsey's lack of speed at his work and his failure to carry out specific instructions for food preparation."
Mr Keirsey missed a busy shift on New Year's Eve because of pains in his leg from a non-work accident and when he went to see Mr Hussein with a medical certificate a couple of days later, he was told he was no longer required.
His boss told the authority he had "simply had enough" of the employee's performance.
But Mr Wood ruled Mr Keirsey's performance was no fault of his own.
"This was not a case of a worker who deliberately disobeyed any instructions or was slack or lackadaisical at work," he said.
Six months and 20 job applications later, Mr Keirsey found new work in the hospitality industry.
He was awarded $9820 for loss of earning and emotional-harm compensation.
Comment was being sought from both parties.