Adam Kershaw lost control of the 7.5 tonne van, tipping it onto two wheels and falling onto a Peugeot 107 with two people inside in the incident near Ingleton in North Yorkshire in July 2018.
A court heard today (Tuesday) how 29-year-old father-of-two Kershaw was driving the van in an "utterly dreadful, appalling and highly dangerous" manner for more than 28 miles when he drove over the Peugeot with Joseph Keane inside, causing him fatal head injuries.
The Peugeot was being driven by Keane's girlfriend Alyssa Henderson when it was hit by the van driven by Kershaw, who was driving home to Mytholmroyd, Calderdale, from a music festival in Sawley, Lancashire.
Bradford Crown Court heard Kershaw had spent the night before drinking and taking ketamine at the Beat-Herder Festival.
Kershaw had been seen swerving across the road into the path of oncoming vehicles and narrowly avoided a coach with 60 school children on board before hitting the couple on the A65 on July 13.
He also hit a stone bridge, leaving a door to the rear of the van hanging open.
He was jailed for nine years on Tuesday, as a judge branded the case one of the "worst" cases of drink driving he had "the misfortune" of coming across.
Judge Jonathan Rose said: "Over a distance of at least 28 miles your driving was utterly dreadful, appalling and highly dangerous to every other road user who had the misfortune to be on the same road as you.
"You were drunk. You were incapable of controlling this very large, very heavy vehicle.
"You had no reason to be driving as you did. It was all done because you were in drink."
The court heard Kershaw was also not licensed to drive the van, which he had crudely converted into an "unsafe" camper van. His insurance was also invalid when he caused the devastating crash.
Prosecutor Jonathan Sharp said several road users had called 999 to report Kershaw's appalling driving on the day of the crash.
He said: "The observed manner of his driving was consistent with him being highly intoxicated throughout and a back calculation confirmed that he was extremely drunk."
Mr Sharp added that the van had tipped onto two wheels as Kershaw took a corner at around 55mph, before falling and crushing the Peugeot that Mr Keane and Ms Henderson were travelling in.
Judge Rose said: "You drove over that car, you crushed it and, in so doing, you killed Joseph Keane."
The court heard that Kershaw did nothing to help at the scene and did not speak to Miss Henderson, who was "covered in blood and hysterical with grief".
But Imran Khan, mitigating for father-of-two Kershaw, said the defendant was "disgusted" about what he had done and had stopped both driving and drinking since the collision.He read a letter from Kershaw, expressing his "deepest apologies" to the family.
Mr Sharp read out statements from Miss Henderson and Mr Keane's father, uncle and best friend, in which they described the impact Mr Keane's death had had on them.
Miss Henderson, who lived with Mr Keane and his parents at their home in Billinge, near Wigan, Lancashire, described how they were celebrating her boyfriend's birthday with a trip away on the day of his death.
She said: "Little did I know this would be our last time together. A happy day turned into the worst day of my life."
Judge Rose told Kershaw: "You brought great sadness, darkness and suffering to all who knew and loved Joseph Keane."
He continued: "What's evident from each of the four victim impact statements is the devastation that Joseph's death brought upon his friends and family and how their lives have been ruined by his utterly senseless and unnecessary death."
Bearded Kershaw was banned from driving for 11-and-a-half years and was told he will have to pass an extended driving test before he can drive again.
The court heard that he had previous convictions for drink-driving and speeding.
Wearing a fabric headband, a beige checked jacket, beige trousers and beige tie, he sat in the dock flanked by two dock officers throughout the hearing.
He occasionally looked at the ground as details about the incident were told to the court but showed no emotion as he was sentenced.