WARNING: The following contains spoilers for Boruto: Naruto Next Generations Episode 193, "Coexistence," now streaming on Crunchyroll.
The role of Hokage was a huge deal in the Naruto series as it was the title character's main ambition. All of Konoha's kids believe this was what the best soldiers had to aspire to -- the ultimate mark of prestige, respect and honor.
Of course, as he grew older, Naruto came to understand the title didn't come with the glitz and glam he thought it would as a kid, but that didn't deter him. Instead, he saw it as the best way to effect true change for all the shinobi nations. Now, in Boruto Episode 193, after meeting so many of these past leaders of the Hidden Leaf, Naruto reveals which one is the most important one in his life as the current Hokage.
Naruto's lucky enough to have met them all, thanks to Hashirama and Tobirama, the Senju brothers and the first two Hokages being resurrected in the Kaguya War. During this, he got a sense of endearment from the former and learned to let go of hateful ways from the latter as they acted as a yin and yang of sorts. Yet Naruto was on this path already, and whilst Tsunade and Kakashi helped groom him to take the role on as he grew into a young adult, even they, as Hokages, weren't as influential as they could have been.
Minato, the Fourth and his dad, could be considered crucial but he died when Naruto was born. When he too was resurrected for the Kaguya War, he helped Naruto improve in battle, but he wasn't anything life-changing. Naruto was a good person already: he simply became a better one by the time all these paths were crossing.
But when it comes to the Third Hokage, Hiruzen Sarutobi, well, that's a totally different story. He's the one in charge when the Naruto series kicked off, and as Naruto tells Shikamaru in the present day, this leader saved him in more ways than we could imagine. The conversation occurs when Shikamaru reiterates they should coop Kawaki up as they don't yet understand his powers. However, Naruto makes it clear he has to be free because that's what Hiruzen did for him before giving his life for the village against Orochimaru.
It's the only way for society to accept Kawaki. It'll also help the teen break his own walls down, which is something Naruto can relate to. After all, when Naruto's parents sealed the Nine-Tails Demon Fox, Kurama, in him, the leader opted not to hide him away. Hiruzen instead had him become part of the village and took care of him like a grandson. And while Naruto was an outcast at first, people eventually warmed to him.
Now, he wants to repay that kindness by adopting Kawaki, understanding what it's like not to have parents. Naruto knows the gifts Hiruzen gave him -- love, compassion and empathy -- have to be passed on. They made him a better soldier but more importantly, a better human, which is what he wants for Kawaki, and all his citizens.