Graeme Wilton was holidaying on the NSW Central Coast with his wife when he fell victim to an alleged unprovoked attack.
More than a month after the assault, Mr Wilton remains in hospital and his alleged attacker is now in custody after an intensive police hunt.
Police say Mr Wilton was on holiday with his wife at Mannering Park on December 12 when he started out on his daily walk.
It is alleged a 22-year-old man driving a white utility stopped near Mr Wilton, 56, got out of his car and punched him to the head.
Mr Wilton fell to the ground.
The younger man allegedly fled the scene, leaving witnesses to contact emergency services.
Mr Wilton is still in Royal North Shore Hospital in intensive care with serious head injuries.
Strike Force Mooneye, set up after the assault, made an arrest on Friday.
Police searched a home on Vales Road at Mannering Park and seized items for forensic analysis.
A man was later arrested in Coonabarabran in western NSW.
He was charged with grievous bodily harm to a person with intent.
He has been refused bail to appear in Dubbo Local Court on Saturday.
A police spokeswoman said the two men did not know each other.
Tuggerah Lakes police Detective Inspector David Waddell said earlier this month police believed the attack was unprovoked.
"His family is distressed and are at a loss as to why anyone would do this to Graeme," he said.