Billy Latham, of Bexhill, Sussex, had faced a manslaughter charge at Lewes Crown Court, but a judge discharged the jury and terminated the trial.
Mr Latham, 36, was cleared when a not guilty verdict was entered.
Peter Morley, 74, died 10 days after suffering a head injury during an alleged row in July 2014 following a reported dog attack on his own pet.
Prosecution lawyers claimed there had been an assault during the incident in Turkey Road, Bexhill.
After the trial ended on 9 October, the Crown Prosecution Service (CPS) said it was considering appealing against the judge's decision to end the trial.
A CPS spokeswoman said had lawyers decided against the move.
She said: "This was a complex case which turned on the prosecution proving beyond reasonable doubt that the alleged assault caused the victim's death.
"The trial judge ruled that there was not a sufficient link between the two and so the case was stopped."
She added: "The CPS sought independent advice regarding an appeal of this decision. After careful consideration we have decided not to pursue an appeal."
A man who faced charges over the death of a dog walker has been formally cleared after a judge ended his trial.