Emar Wiley, now aged 19, was 16 when he stabbed Lewis Bagshaw to death on the Southey estate in July 2019.
He received a life sentence in July 2020 and was locked up at Wetherby Young Offender Institution in West Yorkshire.
But just two months after being sentenced and ordered to serve a minimum of 16 years behind bars, he stabbed a prison officer in the head.
Leeds Crown Court was shown CCTV images of Wiley carrying out the attack with another inmate, in which he used a 'shank' made from prison cutlery.
Kristian Cavanagh, prosecuting, said Wiley, who was 17 at the time, held the weapon to the prison officer’s throat during the attack before stabbing him.
The attack took place on a ground floor residential unit, where inmates were kept in groups of four for education and exercise purposes.
Mr Cavanagh said Wiley approached the officer from behind, put his arm around him and said: “Give me your keys.”
The officer did not take the defendant seriously at first but then saw he had the weapon held to the side of his throat.
The officer grabbed Wiley's hand and spun around but the teenager stabbed him in the forehead.
He then stabbed the officer in the hand as he tried to defend himself.
A 16-year-old inmate, who cannot be identified due to his age, grabbed the officer as he was being attacked by Wiley.
The officer fell to the ground as Wiley continued to make threats and again demanded his keys.
The officer managed to get to his feet and move away before he was attacked again.
He needed hospital treatment to have the wounds glued.
Both defendants were arrested but Wiley refused to attend a police interview.
He later pleaded guilty to wounding with intent and has had an extra 32 months added onto the prison sentence he is already serving.
David Birrel, mitigating for Wiley, said the defendant has been diagnosed as suffering from emotional and psychological issues.
Sentencing Wiley, Judge Andrew Stubbs told him: “I am absolutely satisfied that you are a dangerous young man.
“I think it is likely that you could hurt somebody by doing something like this again.”
Wiley, of Mason Lathe Road, Shiregreen, killed Lewis in an attack on Piper Crescent, Southey.
The judge who initially jailed Wiley described the killing as ‘senseless’.
Wiley was a drug dealer and was described in court as having become ‘desensitised to violence’.
He began smoking cannabis from the age of 13 or 14 before being recruited to sell drugs and he told a probation officer he used to sell £7,500 worth of drugs per week.
When he was sentenced to life, Detective Chief Inspector Jude Ashmore said: “Emar Wiley has ruined so many lives, including his own. He has robbed a much-loved young man of his future and a child of a life with his dad.”