Company director Clive Merrifield, 45, was enjoying an evening meal with partner Idalina Lucas when he politely suggested Billy West, 20, and his girlfriend put the wailing seven-month-old to bed.
West approached the couple's neighbouring table, pulled a bottle of white wine from their ice bucket and brought it down at 'full force' onto Mr Merrifield's skull in front of other customers.
The victim was left with a 'four inch ragged scar' on his scalp following the brutal assault at Parveen, an Indian Restaurant in Theberton Street, Islington, north London.
The former soldier fears the wound makes him look like a thug and is anxious about his image with employees and clients, Blackfriars Crown Court heard.
Karen Robinson, prosecuting, said the clash took place shortly after 10pm on October 9 last year after the baby had been crying for up to half an hour.
West was sitting at a table with his young family and another man, and Mr Merrifield and Ms Lucas were at the next.
'The baby was crying and the lady was seen to get up and down and make moves in an effort to comfort the baby,' said the barrister.
'It was described as consistent and persistent and went on for about 15 to 30 minutes.
'Other customers were looking in the direction of the baby during the course of this period.
'Mr Merrifield said he had had a couple of drinks but describes himself as sober.'
The prosecutor said Mr Merrifield became 'frustrated by the crying and put his head in his hands', and told Ms Lucas: 'I've had enough.'
The victim stood up, approached West's party and said: 'It's a quiet restaurant. We're trying to have a quiet dinner and your baby's not stopped crying.
'Maybe your baby is tired?'
Witnesses described his tone as 'polite and reasonable', but nontheless West's girlfriend held the child aloft and said sarcastically: 'It's a baby.'
Mr Merrifield suggested the tot 'ought to be in bed', prompting West and the second man to stand up and invite him to settle the matter 'outside'.
Staff asked them to leave the restaurant and West was ushered towards the door.
But they 'continued to remonstrate with staff' and CCTV shows West returning to Mr Merrifield, who had stayed sitting down.
'He took a glass wine bottle from its ice bucket and hit him to the back of the head, smashing it on impact,' said the prosecutor.
A witness described West taking the weapon 'high and behind his head and taking aim, bringing it down with full force'.
Mr Merrifield said he 'felt a blow' to the back of his head which left him 'shocked, stunned and disorientated'.
West simply walked to the door and left the premises.
The vicitm was taken to hospital where he was given an emergency x-ray and 16 stitches.