The German coach omitted a clutch of big names for the World Cup in the United States, Mexico and Canada, including Phil Foden, Cole Palmer and Trent Alexander-Arnold.
Harry Maguire, Adam Wharton, Morgan Gibbs-White and Luke Shaw are others overlooked as Gareth Southgate's successor made an eye-catching selection.
England are among the favourites to win the tournament, 60 years after they won their only major international trophy.
Tuchel said the make-up of his squad was more important than picking star names.
"From day one, we were very clear that we are trying to select and build the best possible team, which is not necessarily to select the best 26 most-talented players," Tuchel said at a press conference at Wembley.
"Teams win championships, it's as simple as that."
The former Chelsea and Paris Saint-Germain boss admitted he had had to make painful decisions but said he had "no fear" over his choices.
"It was a given that from these 55 players (in the provisional squad), we have to leave some extraordinary talents and extraordinary personalities at home," he said.
The 52-year-old added: "I like these kind of decisions, even if it took us weeks and sometimes months to verify the decisions.
"I think they bring clarity, I think they bring a certain edge in the end that is necessary."
'Brotherhood'
Tuchel, appointed with a brief to win the World Cup, said he wanted to create a "brotherhood" and believes England have world-class players to make a difference.
"The goal is to try to win it and not be shy about it, and then just to respect the game and the opponents and the amount and the obstacles that come with the tournament itself," he said.
Tuchel added: "I heard recently a quote from Rafael Nadal who said, 'I'm not a winner, I'm a competitor, I'm a challenger'.
"That is basically how I arrive in the US for this tournament. I'm hungry, I arrive with hunger, I arrive with excitement, and I arrive as a competitor and as a challenger.
"And I think that is the role for us as a team, that is how I want the team to play, this is how I want the team to develop, and this is why we picked that squad, and that's why I'm so sure that we picked the right squad."