The 17-year-old senior is now in his fourth season of football at Tokay High School in California, not far from where Hayne is plying his new trade.
A natural athlete, Cornaga was a hurdle runner in Wanganui and has impressed in long jump back in the US.
However it is football - rugby union and now gridiron - which is his true passion.
Having lived with his father Mark Cornaga in Wanganui until his early teens, when he returned to his mother's home so he could prepare to join an American university next year, Cornaga took his abilities to the Tokay Tigers, who play in the Tri-City Athletic League.
He has been the team kicker, getting 33 points (one-point goals) in his second season, and last year despite not being a regular starter, due to recovering from neck surgery, became a school hero with a last-gasp field goal for the Tigers to upend their rivals, the Lincoln Trojans, 22-21.
Cornaga has also been a "slot receiver" on offence, which his father once explained to me is like a flanker in rugby - basically getting the ball from the quarterback off a short-range pass near the line of scrimmage to try and power his way to a 10-yard gain.
Senior sent me a video link of Junior scoring his first touchdown as a wide receiver last weekend, which he also converted.
Getting the pass from quarterback Jared Zermeno, Cornaga was left one-on-one with his marker, right at the sideline, with about four other defenders rushing across to cover.
He left the other poor kid sitting on his rear end as Cornaga stepped perfectly off both feet, and the bewildered tackler fell over and was run into by one of his own players, desperately trying to reach the Kiwi.
In the end, the former Wanganui High School rugby player left bodies everywhere as he glided in and away from two more despairing dives to crash into the end zone for a 26-yard completion on the touchdown.
That took his team out to a 14-0 advantage and they went on to beat the Franklin Yellowjackets 40-12.
The win took the Tigers to a 3-1 record and they remain in the hunt to win their league in Cornaga's final season.
Local media naturally gave their attention to Cornaga's talented teammate Kyle Fleming, who scored two touchdowns to take his season tally to nine.
But even Fleming wanted to share the praise around to all of the offensive line.
"I think the key is that we have so many skill guys that you can't key on just one person. Everybody can score."
This definitely includes Cornaga - it is not necessarily his job in the team to get touchdowns, but when given the chance the former rugby kid showed what he can do, even when alone with four tacklers bearing down on him.
Mark Cornega is flying out to the US to watch his son play in two weeks and plans to take him to the 49ers home game with the Baltimore Ravens. Hopefully, Hayne can suit up, given one of his potential heirs apparent will be in the stands.
In the final countdown to the Charity Plate and Bowl finals at Wembley Park this afternoon, the Wanganui Chronicle must extend thanks to football columnist and haphazard Marist goalkicker Jason King for another stellar season behind the keyboard.
King took on the football reporting last year as a means to subsidise the "First Kicks" programme for youngsters entering the code, and has brought a real passion and depth of analysis to the role.
In these days of limited resources, the Chronicle is indebted to its contributing sports writers.
As we enter another summer season, the musings of Alec McNab in Athletics Insight will be destination reading for the next prospects on the national track and field scene.
Also, every Thursday without fail, the latest column on the Wanganui greyhounds will arrive from Peter Fenemor on the happenings at Hatrick Raceway.