He kept them together for Game 1 of the first round against the Pittsburgh Penguins, when it would have been easy to break the line apart and try to put each of them with at least one experienced player.
Sticking with it has turned into one of Gallant's best coaching decisions of the playoffs because for most of the Rangers' 15 games, the Kid Line has arguably been their best line at even strength.
"That line has been unbelievable for us," forward Barclay Goodrow said. "They bring it every single night. Everyone talks about experience, but it doesn't seem to be phasing them. They're showing up in all the big moments and scoring some big goals for us."
Chytil's growth is the most obvious.
Gallant said on March 2, when he was bringing Chytil back into the lineup after he missed three games, two in a row as a healthy scratch, that he wanted him to play like Zibanejad, meaning with power in his game, strength on the puck and relentless competitiveness.
"He's not a Zibanejad-type of hockey player, but he got the message," Gallant said. "'Fil' is a good kid. He worked hard. He competes hard and he deserves what he's getting right now."
Gallant even moved up Chytil to play with Zibanejad and Chris Kreider in Game 3 against the Carolina Hurricanes after the two top-line forwards were quiet in Games 1 and 2, both losses.
Kreider and Zibanejad got it going that night. The Rangers are 5-1 since Game 3 and 4-0 since the Kid Line has been back together.
"They have greatly improved and contributed throughout the playoffs," forward Artemi Panarin said through a translator. "They're just a joy to watch, to be honest. They're a huge part of the team."
Perhaps the best part for the Rangers is it's their third line.
Lafreniere (14:21), Chytil (13:35) and Kakko (12:25) are eighth, ninth and 12th, respectively, in ice time per game in the playoffs among New York's forwards.
"It's hard to match up against," defenseman Jacob Trouba said. "You always have the top six forwards, the top two lines that play a certain way, and then to be able to have a third line that can create offense, create momentum, chances, score some goals for us, that's huge."
The Lightning had that the past two years with Yanni Gourde, Blake Coleman and Goodrow. They're credited with being a huge part of back-to-back Stanley Cup championships.
Now, it's the Kid Line earning the credit it deserves.
"It started the first game of the playoffs and it just clicked," Chytil said. "We started to play well. We started to play with confidence. We're young guys so we don't think too much about anything else, we're just having fun out there, playing hard and working for the team."