Judges at the Court of Appeal have upheld a sentence given to Lewis Gill, who was found guilty of manslaughter after punching Andrew Young, 40, in an unprovoked attack.
Mr Young later died from a head injury which he suffered when he hit the ground.
Mr Gill, 20, was sentenced to four years in jail for the offence, a decision which provoked outrage.
The incident occurred on November 6 last year outside the Tesco Metro store on Charminster Road in Bournemouth.
Gill later pleaded guilty to manslaughter and was sentenced at Salisbury Crown Court.
Attorney General Dominic Grieve argued today that the sentence was not a proper reflection of the gravity of what Gill did.
But the Appeal Court judges decided there should not be any change to the four years being served by Mr Gill.
More top news
Tonight will start off clear in many areas, but cloud will increase from the east overnight, bringing some light and patchy rain.
Defending champions Arsenal squeezed into the FA Cup final despite a spirited fightback from Reading, who forced extra-time
A detective who led investigations into the Valley Parade fire tells ITV News there is "unequivocal" evidence the disaster was an accident.