Nicknamed "Big Jake" and "Wrong-Grip Jake", Iverson's unique style caused Australian captain Lindsay Hassett, a fellow Victorian, to hide his action during training sessions for the national team.
Hassett prohibited Iverson from bowling to New South Wales batsmen to prevent them from analysing his bowling action, making him more effective in Sheffield Shield matches for Victoria against New South Wales.
This led to conflict with New South Wales batsmen.
When Iverson was put on to bowl during the Tests, Hassett would remove Keith Miller, a New South Welshman, from his position at first slip and move him to mid on, so that he was standing behind Iverson and could not understand how Iverson's bowling action worked.

He explained his action thus:
I woke up to the fact that whichever direction I had my thumb pointing so would the ball break... If my thumb was pointed to the left or offside as I let the ball go, the result would be legbreak.
If it pointed to the right or legside the result would be a wrong'un.
If it pointed directly at the batsmen, it would be a topspinner.

His style was praised by one of his contemporaries, fellow Australian leg spinner Richie Benaud and national captain, who stated in reference to Iverson's innovation that changed thinking about spin bowling:
There have been plenty of spin bowlers around for more than a hundred years but the four, for me, who have broken the mould and made batsmen think seriously about what was coming down the pitch at them, have been Bernard Bosanquet, Jack Iverson, John Gleeson and Shane Warne.

— Richie Benaud
Nicknamed "Big Jake" and "Wrong-Grip Jake", Iverson's unique style caused Australian captain Lindsay Hassett, a fellow Victorian, to hide his action during training sessions for the national team. Hassett prohibited Iverson from bowling to New South Wales batsmen to prevent them from analysing his bowling action, making him more effective in Sheffield Shield matches for Victoria against New South Wales. This led to conflict with New South Wales batsmen. When Iverson was put on to bowl during the Tests, Hassett would remove Keith Miller, a New South Welshman, from his position at first slip and move him to mid on, so that he was standing behind Iverson and could not understand how Iverson's bowling action worked.
He explained his action thus:
I woke up to the fact that whichever direction I had my thumb pointing so would the ball break... If my thumb was pointed to the left or offside as I let the ball go, the result would be legbreak. If it pointed to the right or legside the result would be a wrong'un. If it pointed directly at the batsmen, it would be a topspinner.
His style was praised by one of his contemporaries, fellow Australian leg spinner Richie Benaud and national captain, who stated in reference to Iverson's innovation that changed thinking about spin bowling:
There have been plenty of spin bowlers around for more than a hundred years but the four, for me, who have broken the mould and made batsmen think seriously about what was coming down the pitch at them, have been Bernard Bosanquet, Jack Iverson, John Gleeson and Shane Warne.
— Richie Benaud
Jack Iverson