As a Victorian teenager taken by the Power with pick no. 52 at the 2010 NAB AFL Draft, O'Shea moved in with a host family upon arriving in Adelaide.
He spent six months with them before joining future captain Boak and star forward Robbie Gray.
It was an experience that opened his eyes.
In the six months he spent with his host family, the 21-year-old admitted he was clueless when it came to an elite athlete's diet.
Boak was the club's most promising player in mid-2011 when O'Shea entered the house, and he was as professional off the field as he was on it.
Gray recently moved out, but O'Shea told AFL.com.au that living with his captain gave him important insight into how the League's best players prepared and recovered.
"It's really good to see how professional he is at home and the extra things he does – going down to the beach whenever he's just sitting around to get in extra recovery," he said.
"If he sees something in my game that he thinks I can improve on, he'll let me know and go out of his way to help me do that.
"We get on really well."
O'Shea's increasing maturity is beginning to pay dividends.
He put a disastrous 2012 season to bed over the summer and emerged a hungrier, fitter specimen.
Last year his poor form brought about the headline "O'Dear" in The Advertiser, crucifying him for his four-disposal game in a 22-point loss to the Sydney Swans in round three.
Then, after regaining form and confidence in the SANFL, stress fractures in his foot resulted in season-ending surgery.
The bad press hurt, but the injury was what drove O'Shea through the pre-season.
He worked on every aspect of his game but put particular focus on reading the ball in flight.
The fact he's averaged almost five marks and 18 disposals a game in 2013 compared to three marks and nine touches last year is testament to the work he's done with Power defence coach Matthew Nicks.
"Being able to get back and help out in the air has probably been my biggest improvement and a few little skill things like cleanness at ground level," he said.
"That's probably one of the biggest things I worked on defensively. It's paid off a little bit."
Playing in defence isn't new to O'Shea, whose name correctly suggests Irish heritage. His father was born there and he said he had trouble understanding some of his relatives due to a thick Irish accent.
But he's had vast experience playing in a multitude of positions, as you'd expect of a 193cm utility.
O'Shea has settled into his role as a defender under coach Ken Hinkley and claimed he "hasn't been happier" in his time at Port Adelaide.
Season 2013 has been a step in the right direction, but O'Shea was adamant his best was yet to come.
"I haven't been overly satisfied, I've got a lot of room for improvement," he said.
"But it's been a lot better than the last few years."
Harry Thring is a reporter for AFL Media. Follow him on Twitter: @AFL_Harry
