The British number two from Beverley is remembered fondly by staff at Pocklington School's prep department, where he was a pupil from 2002 until 2006.
Unsurprisingly, he won the junior school tennis championship for three consecutive years.
Kyle, 23, beat third seed Grigor Dimitrov to reach the semi-final of the Grand Slam event and becomes the sixth British man to reach the last four at a Grand Slam in the Open era. He will play top seed Rafael Nadal or sixth seed Marin Cilic on Thursday for a place in the final.
Teachers remember Kyle as a pleasant, quiet and shy boy who even then had a steely determination to win and who excelled at football, cricket and athletics as well as tennis.
Russell Parker, Kyle’s form tutor and the prep school’s head of sport, said:
“Kyle was, and still is, a lovely young man. He was a natural all-rounder at sport but what really set him apart, even then, was his tenacity and will to win.
“He was a tremendous cricketer and we thought he could have made it as a professional. He was also a good footballer and athlete. He still holds three of our school records for under 10s – the long jump, 80 metres and 150m sprint. And when he started playing tennis that forehand of his was amazing even then.
“At the time he was very much a raw talent – not the most elegant and controlled athlete, by any means. But what he had was a determination to come first, and a willingness to go the extra mile. He just wanted it more – and it’s that drive which has obviously helped him to get where he is today.”
Kyle didn’t start playing tennis until he was 10 and it didn’t take long for word of his talent to reach Trevor Loten, then the boys’ tennis coach at Pocklington School, the senior section.
Mr Loten recalled:
“I brought him in to play for Pocklington School in the Under-12 Northern School Boys Championship, which he and his partner won. He was 10 at the time and you could see he was really talented.
“I’ve followed his career ever since and even played against him about three years ago when he came back to his former tennis club in Beverley. He was only knocking about, thankfully, but I had a bit of a chat with him, which was lovely.”
He added: “I think Kyle’s now in the best physical shape he’s ever been. He’s developed his mental toughness and ability to fight back, and reaching this stage of the Australian Open will also boost his confidence no end. I think he‘ll certainly progress to become one of the world’s top 16 players.”
After winning the Davis Cup with Great Britain in 2015, Kyle returned to the prep school days later, took a replica trophy round every class and took the time to talk to pupils. He also signed a tennis ball for every pupil.
“It’s so nice that he still remembers us,” said Mr Parker. “He’s very unassuming and quiet… you wouldn’t know he was a superstar. But in our eyes he always was and is.”
Headmaster Mark Ronan added:
“We are thrilled about Kyle’s success, and we appreciate how he took the time to come back and see us after his Davis Cup win and engage with the pupils.
“As an Old Pocklingtonian he certainly remains true to our Courage and Truth motto. We wish him all the best in his semi-final match on Thursday.”
Kyle grew up in the village of Tickton, near Beverley, and played his junior tennis at clubs in Beverley and Hull. After leaving Pocklington, he spent two years at Beverley Grammar School before moving south to attend a tennis academy in Buckinghamshire. His parents remain in Tickton.