But that's a bit of an understatement - and typical of Roy - he was a very good runner and his exploits are remembered in the Mangawhai Museum.
Staff recounted googling Mr King to show him old stories about himself and his exploits and said while other runners in that era didn't look so muscular Mr King certainly looked like an athlete.
At hearing this, Mr King cheekily poked his tongue out.
"I've got to agree," he said as the staff laughed.
The staff at Parahaki Court where he lives, said he will sing a song for other residents if they ask.
When the Northern Advocate visited him on Thursday and heard about his talent, he obliged with a short song and finished with a grin on his face.
"I could always keep a tune."
He credits exercise as the secret to a long life.
"I've always moved around a bit. I haven't run for a while but I used to do quite a bit. I was quite athletic in my day."
Mr King was still mowing his lawn when he turned 100.
Mr King was born in 1914, in Manunui in the King Country and was one of 10 children, seven girls and three boys.
He grew up in Mangawhai and followed in his father's footsteps and became a dairy farmer.
Mr King married his wife, Alice, in 1939 and she died around a decade ago. The couple had nine children together, seven boys and two girls. Three of Mr King's children have died but he has plenty of grandchildren and great-grandchildren.
Asked if he thought there would be a party in a year's time for his 104th he replied with a smile: "It's hard to know."
The number of people living to 100 and beyond in Northland is increasing, according to Statistics NZ data.
As of the 2013 census, there were 21 people aged 100 or older in Northland. The figure was the same at the previous census in 2006. In 2001 there were 15 and in 1996 there were six.
As for the oldest person in the region? The 2013 Census data showed there were three people aged 101, but whether they are still alive is unknown.
