Police described Jake Telford as a “danger to the community” after a court heard he was also responsible for two other unprovoked street attacks on other victims.
Telford attacked a 20-year-old man when tensions flared after an uninvited group of men turned up at the house in Albert Road, Morley, in July last year.
The men were asked to leave by the woman whose party it was.
They left the house but stayed in the street and began to shout. A guest approached them and asked them to stop but the group attacked him.
When the victim went to his aid he realised he was bleeding and heard his girlfriend shouting “he’s been stabbed”.
The victim was taken to hospital and kept in for treatment to a serious wound to the left side of his torso. Detectives spoke to witnesses and Telford was identified as the offender.
He denied being anywhere near Morley that night and refused to take part in police identification procedures claiming people would have seen his picture on Facebook and often wrongly linked his name to assaults. Witnesses later picked him out on video identification parades but he continued to deny being involved.
While he was on bail, police traced a number of further witnesses who reported seeing Telford fighting with the victim and holding a Stanley knife in his hand.
They were also able to pick him out in identification procedures.
Telford, 20, of Lowood Lane, Birstall, was found guilty of wounding intent after a trial at Leeds Crown Court
He had earlier admitted a separate assault on a 21-year-old man in Market Place, Birstall, in December last year and was found guilty at his trial of assaulting a 20-year-old man with a shovel in Cambridge Road, Birstall, in June last year.
Detective Inspector John Dexter, of Leeds District CID, said: “Telford was prepared to carry and use a knife to attack the victim without any provocation after he and his associates turned up at the party as uninvited guests. The consequences of his actions could easily have been much worse.
“He is clearly someone whose repeated violent behaviour presents a real danger to the community and we are pleased that he has now been brought to justice.
“We hope the significant sentence he has received will provide some level of reassurance to his victims and to the wider community and also serve as a reminder to others of the serious penalties that violent offences such as these will attract.”