Bancroft, who was previously selected for the postponed tour of Bangladesh last year, has ousted Matt Renshaw, the Queensland opener, after he endured a torrid start to his domestic season having shown promise early in his Test career.
Bancroft's numbers, which included an unbeaten 228 against South Australia, became impossible for the selectors to ignore and the main question as the squad approached was whether he would bat at No. 6 or become David Warner's latest opening partner.
Klinger has watched Bancroft's development at close hand for WA and also recommended him to Gloucestershire as an overseas player in 2016. He has seen the player become more attuned his game and learn what sort of a batsman he wants to be.
"I have been lucky enough to have a lot to do with Cameron," Klinger, who is currently at the BPL, told ESPNcricinfo. "I batted quite a lot with him in the first couple of years in first-class cricket, I have spent a lot of time talking to him about cricket and just feeding off each other. I think he has learned a lot in the last two years.
"I think he probably went through a period when he tried to over-score too much. He has gone back to batting long periods of time. He knows he has developed enough shots and skills. He knows if he bats for long periods of time, he can score freely. Mentally he has the fire in the belly to bat long periods."
While his double century in Perth earlier this month is the headline number from his season, it was a pair of half-centuries (76 not out and 86) against a New South Wales side boasting Australia's Test attack that could well have done just as much to propel him to his first baggy green.
"Last year he probably didn't have as good a year he would have liked," Klinger said. "He started this year brilliantly in the one-day competition and certainly in the Sheffield Shield to come and score, I think, 70 and 80 against an attack that had Starc, Hazlewood, Cummins and Lyon was a super effort. To finish off with a 200-odd not out sealed the deal. He deserves his spot. He is the most in-form batsman in Australia at the moment."
And Klinger had no doubt that he would be able to handle the pressure that comes with not only a Test debut, but in an opening Ashes Test.
"I think he has been waiting for a while now. You won't find a harder trainer than him, certainly. He is very astute. I am looking forward to seeing him how he will cope with the pressure. There's no doubt he will cope really well. He will make sure he will have everything in place and ready to go."