Karamvir Dhadda was shopping with a friend at Costcutter in Northdown Road when a fight broke out involving another man, shortly after midnight on Saturday 28 August 2021.
He used an object believed to be a screwdriver to stab the victim six times until a member of the public intervened, allowing the man to break free and run away to safety.
Dhadda, 19, of Doebury Walk in south-east London, was later identified from CCTV footage of the incident and arrested at his home address on Tuesday 7 September.
He was subsequently charged with possession of an offensive weapon and wounding with intent to cause grievous bodily harm, and pleaded guilty to both offences prior to his sentencing at Canterbury Crown Court on Tuesday 8 February 2022.
Dhadda will serve his sentence in a young offender institution.
Investigating officer DC Hazel Edgar-Nevill said:
‘Carrying a screwdriver for violent means is completely unacceptable, especially when it is used to inflict serious injuries on another person like Karamvir Dhadda did in this case. His victim is lucky to have escaped with his life, and were it not for the actions of a brave member of public then that may not have been the case.
‘Dhadda had no previous convictions before this troubling incident, and I hope the experience of being sent to a young offender institution will make him think twice before carrying out such appalling acts of violence again in the future.’