He finished the year with a flourish, playing the final three games, kicking three goals in the first half against the Western Bulldogs in round 23, and in the parlance sometimes attached to young players, looked the goods.
Now it's time to do the work.
"This pre-season is probably going to be the hardest we've had or certainly the hardest I have had in my short career," Stewart told AFL.com.au.
For Stewart, the work started before pre-season officially kicked off this week.
He pulled on his runners several times during his three-week jaunt through Europe with a couple of schoolmates from Melbourne's Scotch College in the off-season.
One pre-dinner run through Lisbon, the picturesque capital of Portugal, sticks in the mind, with the opportunity for extra sightseeing far outweighing any fight for discipline.
"In some respects it was a good way to see parts of the town that you may not have ventured to that day," Stewart said.
At 198cm and 88kg you suspect his frame might have made an impression on the locals as he turned up and down the narrow lanes in Lisbon's backstreets.
It's beginning to be noticed at the Giants.
They know how handy he might turn out to be with his running power, versatility and height.
Stewart's AFL career began slowly with stress fractures in his back forcing him to miss his first pre-season and slowly gain match fitness in the NEAFL.
He made his debut in the final round of 2013 against the Gold Coast, then coach Kevin Sheedy honouring his commitment to give him a taste of senior football, an experience Stewart says set him up well for 2013.
He could not crack it for a senior game early in 2014 but he set himself to play consistent football, playing forward, back and on the wing in the NEAFL.
Stewart kicked 25 goals and won the club's development award but at times early in the season he became frustrated with what he delivered in games.
"I did feel like I was developing … I was aware of what I could do but I probably wasn't able to produce it on a consistent basis throughout that year," Stewart said.
Then he found his rhythm and played well enough to earn a spot in round 21 when the Giants played Melbourne at the MCG.
"I almost approached it as though it was my first game, to be honest," Stewart said.
"I definitely felt a lot better prepared than I was the year before. It was just a really good taste again on the 'G for the first time and gave me a bit of confidence I could perform at the level."
Click here for GWS' 2015 fixture
The Giants smashed Melbourne by 64 points but also lost Jonathan Patton with a knee injury. Since the season ended it has also traded Tom Boyd, Mark Whiley and Stewart's former housemate Jono O'Rourke.
The loss of the two talls – even if Patton's is only temporary – could open up the opportunities for Stewart even further.
"I guess it does," he admitted in a laconic drawl.
"I'd just be happy to be playing wherever, whether that be wing, a position down forward or even possibly chopping out down back. It doesn't really bother me."
The 20-year-old says he is keen to embrace his potential for versatility as an asset.
Certainly it was an attribute his father Craig carried in his 150-game (115 at Collingwood, 35 at Richmond) career.
"It (versatility) is really important in this day and age as well and could also help me potentially earn a spot," Stewart said.
The comment underlines how competitive the environment at the Giants has become in the past year. Nothing is being taken for granted as realistic benchmarks surround each player.
Stewart knows he still has ground to make up as he enters his third season and cites endurance as a focus during the pre-season.
"It's definitely an area I'm still going to try to build on. Without that first pre-season I am still, in some respects, probably a year behind some of the others," he said.
Having just moved into an apartment in Balmain and studying arts at Sydney University, Stewart is beginning to establish roots in the harbour town and re-signed with the club last year.
He can see a chance and he's determined to work hard to take it.
And anyone who saw his sauntering first goal in AFL football when he casually turned his opponent inside out and kicked the ball from outside 50m hopes he does.
"With my second full pre-season, touch wood, it's going to be really important for me to take the next step, so I am really looking forward to it," Stewart said.
