Christopher Furniss-Roe was discovered unconscious in his room, hanging from his bunk bed by a belt tied around his neck.
His father Jason Furniss-Roe cut down his son from the bed's rail and performed first aid on him until an ambulance arrived, Gwent coroners court was told.
Coroner David Bowen, who ruled that the boy did not intend to commit suicide, told the inquest: "He had been naughty and as a result he had been sent to his room.
"It was far more probable he was pretending to hang himself to get sympathy and forgiveness. But it all went tragically wrong," he said in a Mirror report.
Recording a verdict of accidental death, Bowen added: "A heart-wrenching decision was made to turn that [life support] machine off the following day."
The court was told that the boy was in good spirits on the day of the accident as he had competed well at races during his school's sports day.
That afternoon, after coming home from school, the eight-year-old and his little sister had a row outside their house in Pontypool, South Wales, over a broken beach bucket.
Giving evidence in court, his father said he told his son to go and have a shower and then go to bed as a minor punishment. Tragically, he was found hanging just 15 minutes later.
Dr Stephen Leadbeatter, a consultant pathologist at the University of Wales Hospital in Cardiff, concluded that the youngster had died as a result of hanging after a post-mortem examination.
The coroner recorded a verdict of accidental death.