Alan Barefoot, from South Kilvington, was attacked in Market Place in Thirsk on October 16 and had been fighting for his life ever since.
However, North Yorkshire Police have confirmed that he died without ever regaining consciousness.
The 32-year-old became a father again two weeks ago and police have issued a photo of him with his new daughter - as well as a tribute from his girlfriend Charlotte.
She said: “Alan was such an amazing boyfriend, son, brother, and friend to everyone who knew him. He was one of life’s good guys and just an all-round brilliant person.
“He was also the best daddy to our newborn daughter and our hearts have been shattered into a million pieces. It’s not possible to put into words how much we will miss him.
“If anyone has any information about the incident leading to Alan’s death, I hope you come forward and speak to the police. Not only because it’s the right thing to do, but for the sake of our daughter, who now has to face the rest of her life without her beloved daddy in her life“.
The attack took place in Thirsk Market Place at around 9.45pm on October 16, following an incident in The Royal pub that had spilled onto the street.
Police said this is known to have been witnessed by a number of people who had been inside the pub and others who had been in the area.
Emergency services attended and Alan was taken to hospital with serious head injuries where he died on October 24.
A 21-year-old man was arrested immediately after the incident on suspicion of wounding with intent. He has been released on bail.
A 24-year-old-man and 56-year-old man were later arrested on suspicion of wounding with intent and have also been released on bail.
Police have now arrested a 41-year-old man was also arrested in connection with the incident, and said the investigation is ongoing.
Senior Investigating Officer Detective Inspector, Steve Menzies, of North Yorkshire Police’s Major Investigation Team said: “Following the sad death of Alan Barefoot, this is now a murder investigation.
“Last week we issued a CCTV appeal to identify a number of witnesses, and we would like to thank everyone who came forward to help with the investigation following this appeal.
“We would also like to stress that those pictured were potential witnesses and not suspects.
“We are determined to find all of those responsible for this attack which has claimed the life of a young father, who’s baby is just a few weeks old. We will also do all that we can to trace everyone who witnessed the incident.
“I am urging anyone who saw the incident, or has any information which could help the investigation, to please get in touch with us immediately if they haven’t yet come forward.
“This includes anyone who has taken photographs or video footage of the incident to get in touch, as this could be invaluable in supporting our investigation.
“Our thoughts are with Alan’s loved ones at this very sad time.”
Anyone with information is asked to email [email protected] quoting reference number 12210223112.
Alternatively, contact Crimestoppers anonymously on 0800 555 111.