Asif Rehman and Adel Ishaq, both 20, knocked William McKeeney unconscious and repeatedly stamped on his head and body in the street in the Pollokshields area of Glasgow on January 15.
The 57-year-old was walking home from a nearby pub with a fish supper when he was set upon by the pair in an attack witnessed by Mr McKeeney's girlfriend from the window of their home. He died later in hospital.
At the High Court in Edinburgh, judge Lord Uist ordered Rehman to spend at least 16 years and three months behind bars, while Ishaq was told he will be held for a minimum of 16 years.
The judge said the ferocity of the attack led Mr McKeeney's girlfriend to believe they were breaking up a piece of furniture.
It was not until she was able to get a better look that she realised it was a person.
Lord Uist said both men had been roaming the streets looking for trouble on the night of the murder.
He said: "For no reason whatsoever, he was set upon by you two and subjected to a brutal and merciless attack which robbed him of his life.
"It is a shocking indictment of the state of our society that an innocent man should be murdered in a public street outside his own home in this manner.
"Senseless violence of this kind must be suppressed so public safety can be maintained."
Rehman and Ishaq were convicted of the murder last month after a trial at the High Court in Kilmarnock.
Lord Uist said Mr McKeeney was well liked in his local community and that his girlfriend and close family members had been devastated by his untimely death.
He said: "Nothing that I say today can diminish their grief and sorrow."
The judge described how the victim's girlfriend witnessed the attack from the window of their home in Melville Street.
He said: "Such was the ferocity of the violence being employed by you that she thought that you were breaking up a piece of furniture in the street and it was only when she stood on a trunk to get a better look that she realised it was a person.
"She then ran outside and discovered that it was Mr McKeeney.
"He was unconscious as a result of the violence which you had inflicted upon him and he died in hospital three hours later due to haemorrhage from damaged blood vessels in his abdomen.
"At the end of your attack upon him you each walked away, leaving him lying on the roadway in a critical condition and callously did nothing to help him."
Sentencing Rehman, Lord Uist said his background reports made grim reading.
He said: "You have never earned a living and have pursued from the age of 14 a criminal lifestyle, involving the abuse of alcohol and drugs."
The court heard Rehman was convicted of assault in July last year and sentenced to a community payback order which he was still subject to at the time of the murder.
He was also subject to a bail order. He received three months detention for breaking it, meaning he will spend at least 16 years and three months behind bars.
Lord Uist said Ishaq already had a bad criminal record which saw him previously detained for charges of assault, robbery and breach of the peace.
Sentencing the pair, from Pollokshields, Lord Uist said he was in no doubt they both posed a serious danger to the safety of the public.
He said: "You must not assume that you will be released from prison at the end of the punishment period fixed.
"You will be released only when the parole board is satisfied that it is no longer necessary for the protection of the public that you continue to be held in custody."
During the trial it was alleged that the murder was racially motivated but that was deleted from the charge.
After sentencing, a group from the far-right Scottish Defence League stood outside the court building holding placards.