"We first discussed setting up GradConnection in NZ at the cricket," says Milne. "I was looking to do something different and this seemed like a good thing to do.
"I also knew I was at the time in my life when I could take a calculated risk."
Milne launched the website in New Zealand with another friend, tax accountant Tim Watts. Their new careers as budding entrepreneurs proved a steep learning curve.
The emphasis was on sales, with plenty of cold calling and trying to convince sceptical prospective clients of an untested business model.
Pointing to the up-and-running counterpart in Australia had limited success.
"The message was that just because it worked there didn't mean it would work here," says Milne.
But the pair persevered, and within six months had signed up several major clients including his old employer, Telecom and Fonterra. Their website - www.gradconnection.co.nz - now matches more than 60 employers offering graduate and entry-level positions to young Kiwi jobseekers. In Australia more than 100 companies use the service to find new recruits.
Because the Kiwi market is smaller, with fewer formal graduate employee programmes, Milne says companies here use the site more for advertising and branding.
"We've had a 100 per cent re-sign rate," he says. "For some of our clients, it is the second-most-used method of hiring behind their own events on campuses."
Unlike Australia, Milne says government organisations in NZ are often reluctant to employ young people in graduate, internship or entry-level roles.
"We've heard so many different reasons, from it being too difficult to graduates leaving after two years to not having enough work for them to do," he says. "Some say the work is too complicated, others say it's too simple for a graduate."
Milne and Watts, 29, hope to challenge those preconceptions, and will do so from their new base in Auckland, where they relocated this year to meet client demand.
The pair have also established the New Zealand Association of Graduate Employers, hoping to strengthen the sector and foster stronger ties.
Across the Tasman, the three Sydney-based Kiwi directors are set to open GradConnection's first Asian office in Hong Kong.
Casey, who is back in New Zealand to enjoy the World Cup, initially travelled there to talk to companies with operations in Australia.
"But when we got there we realised there was a large demand for our product," he says.
"There's nothing else like it in Hong Kong."