The two-time premiership Tiger, despite having a deal at Punt Road, was spotted touring Alberton in October as trade speculation surrounding the 24-year-old grew.
With Graham soon letting the Power know his future remained at Punt Road, Hardwick admitted the two of them did manage to laugh about the situation, speaking to AFL.com.au.
"We did have a really good laugh actually," Hardwick told AFL.com.au.
"Jack said at the airport that he was going to visit his parents and then he got caught at Port Adelaide. I said, 'I didn't know Ken was your dad!' We did have a laugh. He's a stellar guy and we're glad he stayed, because he's such an important player to us."
Despite Graham being contracted to the Tigers until the end of 2024, Hardwick said he understood that players would seek out more opportunity elsewhere, admitting that it was the "nature of the game".
"I love Jack and our footy club loves Jack. But if Jack wants to have an opportunity to look somewhere else, we understand that. That's the nature of the game. We will never hold that against our players," Hardwick said.
"If our players feel they've got a better opportunity to play at another club, or in a position that they want to play, then we won't stand in their way. Certainly, there has to be adequate compensation coming back the other way. Jack is a very, very good player. But we were up front and honest. We had the conversation."
With Graham remaining at Punt Road as notable off-season inclusions Jacob Hopper and Tim Taranto arrive, the Tigers coach admitted that he doesn't see Graham's midfield minutes shrinking dramatically.
"(His role) won't change too much," Hardwick said.
"He's really good value going through the midfield, but he's also good value across half-forward as well. He's a really important transitional piece for us that we feel can help us in a number of areas of our game, both offensively and defensively. His role won't change drastically. But he certainly will add to our talent pool as well."