Drunk and drugged Guy Shackleton-MacLean attacked a former airline pilot Michael Howard with a steam iron.
Trouble flared when the 20-year-old and three friends were asked to leave because of their thuggish behaviour.
After being hit with an iron, the 46-year-old victim suffered two deep cuts to the back of his head — one exposing his skull.
Guy Shackleton-MacLean then set about the prone man with a baseball bat, leaving Michael Howard with a broken arm and more cuts to his head.
Howard, who was attacked in the drive of his home in Grace Road, Camberley, in the early hours of January 1 last year was left “traumatised” by the incident.
Shackleton-MacLean was found guilty last month by a jury at Guildford Crown Court of causing grievous bodily harm with intent to Howard and common assault on guest Andrew Weller, who tried to intervene.
Judge Derek Inman ordered Shackleton-MacLean, of Prospect Avenue, Farnborough, to be detained in a young offenders’ institute for four years.
“This was a very serious offence of violence,” the judge said, passing sentence at Middlesex Guildhall Crown Court.
“You and your friends had all had a lot to drink and now it seems were taking cocaine.
“Your collective behaviour caused offence to your host and you were asked to leave. If you had done so, there would have been no further trouble.”
The judge said the group did leave but with “some fuss” and damaged the garden.
“Mr Howard had been in bed and got up to ferry friends, including children, home. He was sober, he had nothing to drink.
“He met your group on the road and as a result of what happened you all decided to go back to his house and, as you told the jury, resolve earlier problems.”
Howard had gone inside and returned with a baseball bat to chase the gang off his premises.
Shackleton-MacLean also went into the home and returned with the iron.
The judge said: “You followed him down the drive and threw it, hitting him on the back of the head and causing two deep cuts, one reaching the bone.
“You then both wrestled on the drive and you, being much bigger, removed the baseball bat from his grip and hit him up to four times.
“He put up his arm to defend himself and you hit him on the arm, breaking the bone.”
James Ingram, defending, had told the court Shackleton-MacLean was high on his first snort of cocaine.
“It seems it was the first time he had experienced it, and may go some way to explaining his actions,” the barrister said.
He described Shackleton-MacLean as a follower rather than a leader and claimed the ringleader of the gang had never been charged, although two other men were cleared of assault by the jury.