Jack Green attacked the woman in Union Street, Canterbury in October 2021 after an altercation outside a takeaway in the area.
Green, who can be named following a ruling by a judge at the city’s crown court, admitted wounding with intent at a hearing on 6 January 2022, having previously pleaded guilty to using threatening words or behaviour.
The 16-year-old, of Pye Alley Lane, Whitstable, was jailed for four and a half years.
Green and his friends got into a conversation with the victim’s group at the takeaway in Northgate at around 2.30am on 23 October.
When one of the victim’s friends disclosed his sexuality, Green made homophobic comments and followed the victim and her friends after they tried to leave the area.
Green and his group then armed themselves with items found in a telephone box and threw bricks and bottles towards the victim’s group.
When confronted over his behaviour, Green pulled out a small knife and struck the victim to the chest. Green and his friends then ran from the scene.
Police and paramedics attended and the victim was taken to a London hospital. She suffers ongoing complications due to the attack.
Officers reviewed CCTV from the area and recognised Green as the attacker. He was arrested three hours after the assault.
PC Byzid Al-Mahmood, Kent Police’s investigating officer, said: ‘This was a heinous attack on a young woman who was trying to defend her friend after Green’s appalling comments.
‘I am pleased a swift and meticulous investigation by officers from Canterbury’s Vulnerability Investigation Team has led to a dangerous young offender being removed from the streets.
‘I would like to pay tribute to the victim’s bravery in supporting this prosecution and in speaking in court. I hope the sentence gives her a sense that justice has been done.’
Inspector Guy Thompson, of Canterbury Community Safety Unit, said: ‘Canterbury is a welcoming city which is home to a diverse range of people.
‘Kent Police is fully committed to tackling hate crime of any kind and will respond to all reports by seeking out perpetrators and, where possible, bringing them before the courts.’