He asked the court for reparation of $60 for the broken letterboxes.
Defence lawyer Peter Stevens handed up references from neighbours stating Walker was a "very obliging and helpful neighbour".
Mr Stevens said Walker had a drink problem: "He's attending AA and is finding it very beneficial ... he realises he was stupid."
The defence lawyer told the court Walker had not been in trouble for 13 or 14 years and suggested the judge convict his client but discharge him without further penalty.
Judge Ellis asked Walker about the fact the police had requested the axe's destruction. Walker replied he had another.
"There isn't much point in destroying the axe when he could get another one from The Warehouse for a few bucks ... you should get that axe back and use it for the right purpose," the judge said.
Judge Ellis convicted Walker and discharged him after ordering reparation of $60 for the letterboxes.