Hamilton announced earlier this year that he would be leaving Mercedes at the end of this season and joining Ferrari as Charles Leclerc's team-mate for 2025.
And although Vasseur has so far, out of respect for current driver Carlos Sainz, been reluctant to talk much about Hamilton, he has now offered some background of the reasons for his determination to lure him on board.
In an exclusive interview with Motorsport.com, Vasseur said that Hamilton's arrival brought gains that would start many months before he even sat in a car for the first time.
"The input of Lewis or another driver is not just about qualification lap time and so on," said Vasseur.
"It's the finality of the job. What we all collectively can see Saturday or Sunday, at the end of the day, the job of the driver is much wider.
"It's starting sometimes six or eight months before the season, to be able to work on the next project, to bring his own experience, his own view on what we can do, or how we could do it and so on and so on."
Vasseur believed that, with his organisation in its current guise still in its infancy, having someone with Hamilton's vast experience of the board would be priceless in giving it a proper direction to head in.
"I think we are still a young team. It's not just a matter of age, but it's a matter of experience together, and wins together.
"So that means that we are quite green, or quite young, and to have someone into the loop with such a big background and such big experience will impact for sure.
"We have time to discuss this with Lewis and, for me, into the building process of the team - you want to have a long-term view and for the next cycle.
"I'm not speaking about '24 or '25, it's about cycle and it's where clearly, we have to do steps.
"We made some improvements already I think, compared to 12 months ago, to involve the drivers much earlier into the project and to build up the characteristic of the car with them.
"I think we are going in the right direction. But for sure Lewis will add value."
Hamilton secrets and Newey gossip
One of the other encouraging aspects Vasseur found about Ferrari's signing of Hamilton was that the news did not leak from the team until the 11th hour.
Whereas previously Ferrari had been widely known for not being able to keep information within the confines of the Maranello factory walls, it was only on the morning of Hamilton's announcements that the story properly hit the media.
"We had no leaks," said Vasseur, who suggested that even the stories on the morning of the announcement had not come from Ferrari.
"I think it was done by purpose by someone from the UK," he smiled.
He added: "I really appreciated that we are a small group, and we worked for months, and we are able to go until the end and had no leakage. It was a good one."
Vasseur said one of the things he has addressed specifically since joining as team principal was getting rid of secret information getting out.
"We had some leakages at the beginning when I joined, even before I joined because I understood in the press that I will go to Ferrari before I started the discussion with Ferrari.
"In the last six months, you had gossip in the press, but it was gossip and not real leaks from the team.
"There was the story with [Adrian] Newey seen in Bologna because Newey was going to Mugello [to test]. That's not a leak!
"I don't want to make any judgment on the past, but I can't complain. I had more leaks at Renault, for example. Renault, I was saying something in the debrief, and then it was in that afternoon on the websites."
