Asked if the Three Lions captain was undroppable – even after his muted start to Euro 2020 – Southgate insisted his position was not in doubt.
The England manager has already confirmed Kane will start against Czech Republic in Tuesday’s final Group D game.
Ahead of that match, he said: “I think the only thing that is relevant is what I have said already this week - his importance to the team.
“He’s been our best player, our most influential player, our most important player for a long period of time and of course there have been moments where the likes of Raheem (Sterling) have had periods where he has been critical for our success as well in terms of the goalscoring.
“But Harry has consistently been our top goal-scorer since I have been in charge. His record is phenomenal and he is a hugely important figure for us.”
Kane has been substituted in the games against Croatia and Scotland, and is yet to register a shot on target.
Southgate has Dominic Calvert-Lewin and Marcus Rashford as potential replacements for the Tottenham striker – who is the subject of a +£100million bid from Manchester City – but the England manager is adamant Kane remains his first choice.
“Harry I’m sure is going to be playing well for us and will have a big impact for us,” he added. “I am not worried about that.
“Are we pleased to have Dominic in our squad? Absolutely. He’s a very good centre forward and he had a big impact for us in the autumn.
“It’s good that we have him and Marcus who can play as nines in the team. I think they understand in terms of their challenge with Harry – and obviously Marcus can play wide as well.
“They understand who our best number nine is and the scoring pedigree and the importance to the team of Harry’s status and his role for us.”