Paul Jason Sultana was found guilty in the NSW Supreme Court on Friday of the January 2023 strangling murder of mother-of-two Dayna Isaac.
But rather than leaving in a prison truck, he was rushed out of court on a stretcher tended by paramedics.
Sultana stabbed himself in the left arm with a sharp implement after hearing Justice Peter Garling's verdict in the King Street courthouse.
The 35-year-old was tended to by sheriff's officers and court staff while an ambulance was called.
He sobbed loudly and had a bloodied left arm as he was wheeled out of court by paramedics.
The incident played out in front of Ms Isaac's family, including her father Garry English.
He told reporters outside court that Sultana's guilty verdict was a good outcome for his "princess".
Ms Isaac's murder followed a brief relationship between the two, the court was told.
The relationship was "unsettled" and involved a jealous Sultana being unable to accept Ms Isaac did not want a long-term relationship, Justice Garling said.
Mr English outlined conversations he had with Sultana to the court, including one in which he said his daughter was not interested in pursuing a romantic relationship with her eventual killer.
"I said to him 'Paul, Dayna likes you as a friend and nothing more'," the victim's father said in his statement.
"He got in my face and told me that I have to tell Dayna that he was good for her."
The day before the murder - and against Ms Isaac's wishes - Sultana moved some of his belongings into her apartment in the western Sydney suburb of Penrith, where the murder occurred.
The next day, a woman heard an altercation between the couple, an incident she described in a message as "the neighbour beating the shit out of his missus".
The neighbour said she saw Sultana leave the flat with a green Woolworths bag after the altercation.
"It struck me really strange that somebody was walking away, just so casually and calmly after what I just heard," she told the judge-only trial.
Police discovered Ms Isaac's body in the flat several hours later and a forensic analysis determined she had been strangled to death.
The trial also heard evidence from Sultana's mother, Janet Tsiliris, who was called by her son in the aftermath of the murder.
The killer later picked up his mother in Ms Isaac's car and took her to the crime scene.
He repeatedly told her "it's bad", Ms Tsiliris's police statement said.
"I walked in the front door and saw blood in the entry way near the lounge room on the floor," Sultana's mother told investigators.
After seeing Ms Isaac with blood on her face, Ms Tsiliris ran out of the unit yelling "I'm gone, I'm out of here."
After his mother left the flat, Sultana drove Ms Isaac's car into deserted bushland and set it on fire.
Throughout the trial, the killer claimed he had been "deeply asleep" on the couch in the flat at the time of the murder and a third party must have been responsible.
But Justice Garling dismissed his story, finding there was no unidentified culprit who carried out he murder.
When asked why he didn't ring the police and why he burned the car if he was not responsible, Sultana claimed he acted out of panic and fear of being falsely blamed for her death.
He is expected to face sentencing before the end of the year.
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