"His leadership qualities are invaluable to us as a team", the 47-year-old claimed.
Hart felt Kane's secret was his simplicity in front of goal.The striker has made steady progress over the past two seasons for his club, scoring 25 and 29 goals to pick up the golden boot twice in succession.
However, Southgate insists Kane has not been permanently awarded the captaincy and any decision over England's long-term captain is now on hold. His remarkable run of form - he has 36 goals in 31 appearances in 2017 for Spurs - has seen him dominate headlines but there is a maturity about the way he speaks.
Southgate has rotated the armband between Kane, Henderson and Chelsea centre-back Gary Cahill in recent months after Rooney lost his place as a regular starter.
Be it his Captaincy of the England team as they head into their World Cup qualifier against Slovenia, the possibility of a move overseas, or even his newfound dietary preferences. I think it's the correct decision [to appoint him captain on Thursday] but I would give it to him permanently.
"He recognises his responsibilities and how things will be viewed, and how his world is changing in terms of the attention on him and the spotlight on him", said Southgate.
Paper Round's view: We'll assume this "battle" follows a period of quiet self-reflection by Barkley, who's concluded perhaps a salary of £150k per week (his rumoured self-valuation back in the summer months) was a little steep, after all.
"Of course we're working with the team all the time, we're clear what we're working on, on the areas we want to improve and we're here to win".
Meanwhile, Kane's team-mate, Dele Alli, misses the game through suspension after his middle-finger gesture in the win over Slovakia.
'They got £80m for Gareth Bale and they didn't really do a lot with that so they can't afford to let him go. However, I just want to make this point: at this point in time, Tottenham Hotspur has a player who is potentially the most valuable striker in the world on its roster, and he doesn't want to leave.
"It's more just planning it: when we have double [training] sessions, maybe higher carbs; when the sessions are a bit lighter, it'd be lower".
"We have several people that I think can step into that fold now - and that can only benefit us as a team".