Thirty-seven years ago, double world champion cowboy Jack Roddy, of the United States, hosted McCarthy and his friend Brian Robinson at his place at San Jose.
The experience McCarthy gained there stood him in good stead for the rest of his rodeo career and he has never forgotten the favour.
"He had some very, very good cowboys and made us very, very welcome. He ran schools all over America, which cost quite a lot of money.
"But it never cost me a cent. So the only way I can repay him is to help people in my arena," McCarthy said in an interview with the Otago Daily Times yesterday.
Today and tomorrow marks the 25th anniversary of the McCarthy Jackpot Rodeo, which focuses on giving young entrants their first taste of the sport, while allowing others to introduce new horses to competition, test their tried and true steeds and catch up for some off-season socialising.
McCarthy, with the help of loyal locals, pays for the event himself and does not expect any financial return.
This year he has invested $6000 in prize money and trophies.
Upper Clutha youth are the beneficiaries of Mr McCarthy's debt of gratitude to Roddy but McCarthy still keeps in touch with his mentor, who is now 79 years old.
"I was at the world national finals in Los Vegas last year and was talking to him there.
I've been to the world national finals for the last three years and intend going back for the 50th anniversary [in December]," McCarthy said.
Another important mentor he had was Lake Hawea Pony Club instructor Diana Gawn, now known as Dee Gordon, who taught McCarthy to ride when he was about 7.
"I rated her up there then and I still do," McCarthy said.
He was also encouraged by the Robinson family, who were in the pony club but also involved in the rodeo throughout New Zealand.
"I started going to rodeo and I got bitten by the bug. I was making a hell of a lot more with rodeo than with my jumping horses.
"So they got sold and I have never regretted it to this day," McCarthy said.
He no longer breeds horses for rodeo, preferring to "panel beat" problem horses into shape instead.
Early in his career, he made do with any horse because there were no quarter horses around.
He is proud several top cowboys earned their first cheque at his jackpot rodeo.
He estimated about one in 10 of the youngsters who tried calf roping and barrel riding events on the McCarthy farm furthered their career in the sport.
The success stories have included Laurie Latta, of Balclutha, Richard Mee, of D'Urville Island, Charlie McDonald, of Hampden, and Shane Cooper, of Luggate.
McCarthy's offpsring, Patrick (27), a Christchurch carpenter, and Kate (29), a Timaru nurse, also achieved highly in rodeo events and are back for this weekend's anniversary.
And McCarthy's own achievements cannot be overlooked.
He is a former national title-holder in steer wrestling and team roping and still competes regularly on the rodeo scene.
One international highlight was winning a go-round in the steer wrestling at the 1978 World Titles Rodeo in Sydney.
Unfortunately, he was unlucky in his second go-round and dropped down the points table.
But his best international moment was also his biggest "blooper".
"It was one of those highlights which I didn't do very good at, I must say. I was at a rodeo [in Colorado] and I drew the bucking horse of the world. I didn't cover him [stay on for 10sec] but I did get him to the other side of the arena.
"That was a big thrill to draw a big horse like that," McCarthy said.
The McCarthy 25th Anniversary Jackpot Rodeo is at McCarthy Rd today (adults' events) and tomorrow (children's and ladies' events). Entry is free.
Prizegiving is at the Lake Hawea Motor Inn on Sunday evening.
