Detectives investigated after the 17-year-old victim was stabbed in Billy Fury Way, off Lithos Road NW3, on 6 November 2018.
The victim was taken to hospital, where he was treated as an inpatient for around two weeks, before being discharged.
On 8 November 2018, officers arrested Terail McDonald, 17. He was charged the following day.
Following a trial at Blackfriars Crown Court, McDonald was found guilty on 7 May of causing GBH with intent and possession of an offensive weapon.
He was sentenced at the same court on Tuesday, 11 June, to six years’ imprisonment for GBH. He was also sentenced to 18 months’ imprisonment, to run concurrently, for possession of a knife.
Reporting restrictions were lifted, enabling McDonald to be named despite his age.
Detective Constable Chris Shepherd of Central North Command Unit said: “The stabbing appears to have been the result of an argument between friends, which escalated needlessly and violently to leave the victim suffering critical injuries.
“This case serves as a reminder of the danger of carrying a knife. The victim did not support the ongoing police investigation, however the determination of investigating officers ensured that McDonald received the custodial sentence that this violent knife crime warranted.”
Young people who have information about violence or knife crime can visit fearless.org where they can pass on information anonymously. Fearless is part of the Crimestoppers charity, and is also independent of the police.