"I'm not the only one to achieve this but to be part of that exclusive group of auctioneers who have been in the industry for such a long time is pretty special."
"From an industry perspective, it is a bit of an achievement."
Child admitted having to keep his emotions in check when he brought the hammer down for the 10,000th time, on 12a Kingsley Place in Mount Maunganui, which sold for $850,000.
"It was a proud moment, there's no doubt about that."
The property market had changed "a lot" in 21 years.
"The lowest sale price I have brought the hammer down for was $36,000, and the highest so far has been for $7.32m."
Child said he had loved every bit of his career.
"I love it. I love helping people move to the next chapter of their lives. That is still what gives me a big buzz.
"Buying and selling real estate is a life-changing event and I still get the biggest buzz bringing the hammer down for first-home buyers. You know how hard it is for them.
"The other thrill I get is seeing vendors that are equally excited about selling to a first-home buyer."
One first-home buyer in the auction room recently did the "biggest dance I have ever seen in my career".
"She was jumping a couple of feet of the floor. It was so exciting."
But at the end of the day, Child said the auctioneer's role was just the "icing on the cake" to the salespeople's hard work.
At 67, Child said he would soon have to start slowing down but he had no intention of going anywhere in the immediate future.
"I will stay involved for as long as I can.
"But when I'm ready to retire I will make sure we have the right person for the job. That's important to me."
Simon Anderson, managing director of the Realty Group, which manages Eves and Bayleys, said the company was proud of Child for reaching this milestone.
Anderson said Child also volunteered his time at charity auctions and his attention to detail was second to none.
"Grant sets extremely high standards for himself in every auction he calls. He should be proud of achieving this - and he's not stopping here, of course.
"I can't imagine there are many people across New Zealand that have called 10,000 auctions. It is very significant."