Jack, 22, battled for three years to get on an AFL list, repeatedly overlooked until Collingwood finally threw him a lifeline in the 2013 Rookie Draft, taking him at pick No.41.
Eighteen months younger, Sam had similar troubles and the Rookie Draft was also his saviour, taken by Greater Western Sydney with the first pick in 2012.
The main stumbling block for both players appeared to be their hips. Jack had two bouts of hip surgery before spending a year with Williamstown's VFL reserves in 2012.
Sam sat out the testing at the draft combine due to his own hip issues and was subsequently bypassed in the national draft.
Already close, the setbacks made the bond between the blond-haired brothers even tighter. And only increased their determination to prove the doubters wrong.
"There is always a little bit of a chip on your shoulder missing out on something you wanted so badly to begin with," Sam told AFL.com.au.
"And then getting an opportunity to maybe prove a few people wrong – definitely for me personally and I think Jack's the same.
"Jack ended up having hip operations before he was drafted.
"I spoke to 15 or 16 clubs at draft camp, but I didn't test because I had bad hips, so I can imagine why it seemed like a bit of an issue.
"But without surgery I played almost every game in the reserves in my first season with the GIANTS.
"I think it was blown up a bit, but it's all in the past now.
"It's brought us together, having gone through the same thing, and definitely there's a fire burning and you want to prove everyone wrong that didn't give you the chance."
As a teenager, Sam planned to pursue a career in basketball, hoping to link up with a college team in the United States. He is also regarded as a more-than-handy junior volleyball player, although he says his ability in that sport has been "blown out of proportion".
Ultimately he got burnt out with basketball and started concentrating on footy, moving to Melbourne's Wesley College in year 10, where he would play alongside current teammate Toby Greene.
A couple of days after missing out at the national draft, a call came through from GWS list manager Stephen Silvagni with the news he'd been dreaming of – the GIANTS would be taking him in the rookie draft.
GWS defender Phil Davis joked this week that "Frosty likes to call himself another one of our number one picks", alongside Tom Scully, Jon Patton, Lachie Whitfield and Tom Boyd.
He managed to play three senior games late in his rookie year and another two last season, used variously in the forward line, in defence and as a pinch-hitter in the ruck. But halfway through 2013 Frost began training and playing strictly as a key defender and that's how he now considers himself.
At 194cm and 93kg, he has the size and strength required down back, and unfortunate injuries to Davis and Tim Mohr have given Frost the opportunity he needed.
He has played all three games in 2014 and proven his versatility by spending time on players such as James Frawley, Gary Rohan, Lewis Roberts-Thomson and Tom Hickey.
"He had a terrific pre-season," GWS coach Leon Cameron said of Frost.
"We took it to him and he responded really well in his third year.
"An opportunity arose with Tim Mohr going down and obviously now with Phil out for a little while.
"But the good thing about Frosty at the moment is he's just loving his footy.
"He trains every week, he reviews his game really thoroughly, he knows there's an opening there for him and we see him improving week by week.
"He's in pretty good form at the moment."
The similarities with his brother don't just include being overlooked in national drafts and overcoming hip problems.
Jack managed two games in his rookie year of 2013 before a knee injury interrupted his progress and has played all three games for the Pies this year.
Some of his 2014 opponents would be enough to give any defender nightmares – namely Matthew Pavlich, Lance Franklin and Tom Hawkins. His effort against Franklin in particular earned high praise from his coach Nathan Buckley.
"'Frosty' has put a lot of work in over the last couple of years," Buckley said following the round two win.
"He's a young player with great athleticism, and the thing that he needed to convince himself of was that he belonged.
"He's shown a real want and belief to take the game on."
Unfortunately Sam was in Melbourne for GWS' clash with St Kilda while Jack was running onto ANZ Stadium, so he wasn't able to watch his brother take on Franklin. But they speak regularly and he is understandably thrilled it is all coming together for his big brother.
"We're very close," Sam said. "We're only 18 months apart so we've grown up very close.
"It's great to see him going well.
"After being overlooked a couple of times in the draft he worked on a few things and Collingwood gave him an opportunity and he's playing pretty good footy at the moment."
It's obvious that Cameron's faith in Sam is also growing, with the coach saying this week he would be happy to throw him onto any of the AFL's best key forwards.
Western Bulldogs Stewart Crameri and Liam Jones were the names Cameron mentioned as possible opponents ahead of Saturday's round-four clash in Canberra.
Not only does Sam now feel that he belongs, he is excited about being part of a GWS side that has started the year with two early wins and, just like the Frost brothers, is showing great potential.
"There's a few jokes here and there about finals, but we're obviously aware that it's only been three games," he said.
"We've had a good draw to start the season, we've got a long way to go and a lot of tough games to come.
"Every week is a new challenge and a different forward to play on.
"But it's an exciting feeling."
