The jury at Belfast Crown Court returned the guilty verdict against Stephen Charles McCaughey following three days of deliberations.
The 26-year old, from Shackleton Walk, was also found guilty of possessing a shotgun with intent to endanger life.
After being told he would serve a life sentence in prison, Mr Justice Weir remanded McCaughey in custody.
As he was being led from the dock, he shrugged his shoulders to relatives in the public gallery.
Philip Strickland, 37, died on the outskirts of Comber on 11 January 2012.
He was shot in the leg at a yard on the Ballyglighorn Road before being bundled into the boot of his own car and driven a short distance to the Ballydrain Road, where he was shot in the face at point blank range.
McCaughey - who went on the run for several days following the murder - admitted being present when Mr Strickland was killed, but consistenly denied involvement in the murder.
He is the second man to be found guilty of murder.
Philip suffered a brutal and cowardly death.
Detective Chief Inspector Karen Baxter
On Monday his co-accused, 56-year old Jimmy Seales from the Ballykeel Road in Hillsborough, was found guilty by the jury at Belfast Crown Court of murdering Mr Strickland and possessing a shotgun with intent.
Two of Seales' sons, Ian and Jason Weir, both 29, have already admitted their role in the murder. Following the two guilty verdicts, all four men have now been handed a life sentence and will learn at a later date how much time they will spend in prison.
McCaughey, who went on the run for several days following the murder before handing himself in at a police checkpoint set up in the West Winds Estate, said he was asked to go to the yard by Jason Weir, who told him there may be a bit of trouble.
McCaughey told the jury during the six-week trial that he "did what any friend would do" and went to the yard on the fateful evening, but said he wasn't aware a weapon would be present or that anyone would be killed.
It has always been the Crown's case that all four people - Jimmy Seales, Ian Weir, Jason Weir and Stephen McCaughey - went to the yard with the joint purpose of inflicting serious injury on Mr Strickland, and that by lending assistance to each other, all four participated in the crime and were equally guilty.
Speaking outside Laganside Courthouse, Philip's twin brother Andrew Strickland said: "On behalf of my family, I would like to take this opportunity to thank the PSNI and members of the legal team for their hard work in bringing to justice those responsible for Philip's murder."
The grieving brother continued: "It has been a diffcult time for us, however we are happy with today's outcome and appreciate the support of everyone over these last two diffcult years."
The officer who led the investigation, Detective Chief Inspector Karen Baxter, said Mr Strickland was a hard working man who had been murdered because of a dispute on social media.
"The vast majority of the local community were shocked and outraged by Phillip's death. Many people worked with us to provide information and assistance which has culminated in the guilty verdicts. I want to acknowledge their co-operation and thank people for working with us," she commented.
"Sadly, a small group of individuals did not co-operate. Some of them are among the nine individuals who have been charged and convicted for the roles they played in Phillip Strickland's murder. It is up to the court what happens to them now.
"I hope in some small way these convictions, four of which are for murder, provide a degree of comfort to Phillip's grieving family."