McKenna and Celebrini spent part of the summer training together in Vancouver. That gave McKenna an up-close look at how Celebrini goes about his business, which has quickly led him to becoming one of the best players in the NHL just 158 games into his own career.
Celebrini had 115 points (45 goals, 70 assists) in 82 games last season, nearly doubling his production as a rookie (63 points; 25 goals, 38 assists in 70 games. He was a nominee for the Ted Lindsay Award given to the most outstanding player in the NHL as voted by fellow members of the National Hockey League Players' Association. He has 11 points (three goals, eight assists) in six games this season.
"Just how hard he works," McKenna said of what he noticed training with Celebrini. "We spent a lot of time on the ice and in the gym and I think honestly that translates to his on ice stuff.
"When you're working hard off the ice, it just improves your game. To see him have that motivation at a young age is pretty cool."
Being the No. 1 pick always carries immensely high expectations, though each situation is different. For Celebrini, the Sharks were still in a building phase when he entered the League in 2024-25, allowing them to be more patient as he acclimatized.
For McKenna, the Maple Leafs began this season with the expectation of making the Stanley Cup Playoffs, meaning they're looking develop him while prioritizing wins. That means less patience for mistakes, and doing all of this under the spotlight of one of the busiest hockey media markets in the League can be daunting for an 18-year old.
Maturity, McKenna's sense of humor notwithstanding, is a word often used to describe the native of Whitehorse, Yukon.
"He's mature in some ways," Maple Leafs forward Nick Paul said. "I mean, I sit beside him and his jokes are still 6-year old-eque but he's a mature guy. He knows he has the support of the team, and he knows it's going to be better moving forward."
After starting the season without a point in three games, McKenna was on a four-game point streak (two goals, three assists) until he was benched from the 10:32 mark of the second period and played just 6:36 in a 5-4 overtime loss to the Buffalo Sabres on Thursday.
"Obviously, you want to play, but yeah, we (coach Jim Hiller and himself) had a good talk," McKenna said before a 4-1 loss to the New York Islanders in Toronto on Saturday. "We have a good relationship together, me and Jim.
"He said it had nothing to do with my play, which is obviously nice to know. It doesn't really take away from your confidence at all, so (I) appreciated him reaching out, and I trust him. I trust the team. That's what they want to do, so I'm willing to play whatever role this team wants."
McKenna played a season high 17:56 on Saturday, the third-highest among Maple Leafs forwards, and had four shots on goal while also being elevated to the top power-play unit in the absence of forward John Tavares, who is week to week with a lower-body injury.