Keogh's 10-year-old son drove the 4WD vehicle home with his fatally injured father, who was rushed to Kaitaia Hospital where he later died.
In sentencing, Justice Faire said Harris stabbed Keogh in front of four children who not only witnessed the attack but were forced to try to save their father's life. Justice Faire said the attack was something no young person should have to go through.
"They truly have suffered a great loss," he said.
Keogh's family, including his parents Morag and Rowland Keogh, read victim impact statements while directly facing their son's killer.
Morag Keogh said Harris' claim of self defence was weak.
"As a farmer and a pig hunter, you knew exactly where to stab him. You showed no mercy. You left him to die like a stuck pig.
"In my heart, you took a life and you should be serving life," she said.
Rowland Keogh stormed out of court while Justice John Faire delivered his sentencing remarks.
Morag Keogh later told the media her family thought the five years and nine months imposed on Harris was "too light" and the family was "extremely unhappy" with the sentence.
They thanked people for their support and said the focus would now be on Joseph Keogh's four children and his two sisters.