He was with the United States at the 2014 IIHF World Junior Championship when his junior team, the Plymouth Whalers of the Ontario Hockey League, played at Comerica Park in Detroit.
Last season he played three games early in the season for the Blackhawks but spent most of the season with Rockford of the American Hockey League.
When he made Chicago's opening-night roster and earned a regular role this season, Hartman began to let himself daydream about the playing in the Winter Classic.
"It's really exciting," he said. "I know last year I was kind of up and down. I was hoping to be up at the time of the [Stadium Series game], because I thought that would be fun, but I wasn't. So to have a chance to do it this year is going to be really cool, just to bring my family in and experience the whole thing."
It's an experience that Blackhawks coach Joel Quenneville never tires of watching.
He's been around for the four previous outdoor games Chicago has played and has seen a lot of smiles and wide-eyed looks from first-timers.
"It's a privilege and a special feeling to be a part of them, especially for those new guys skating around," he said. "It will be something they've never experienced, with the crowd and the hoopla and the excitement. It's different playing in the game. It's a real game and you're playing for keeps. You [always] hope, as a player, you get that privilege to be a part of it."