The frontrunner in the Conservative leadership race made the intervention in an exclusive interview with The Yorkshire Post, in which he set out his wider vision for the region.
The former Mayor of London said his priorities for the North of England were to improve transport infrastructure, increase investment in education and roll out superfast broadband to support small businesses.
And he admitted that the area had been “neglected” under previous Governments.
“I think whole areas of the country, including the North, have been neglected,” he said.
“For too long we’ve had a vision of Britain... the Treasury has had a vision of Britain, which is that if you want to invest a pound and get the best return, you put it in London and the South East.
“That’s been the philosophy and it’s time to recognise that that philosophy has got to end and we’ve got to start unleashing the potential of the whole country.
“It’s time to level up and it’s time to recognise the potential of the North.”
This comes after Northern Powerhouse Minister and close ally of Mr Johnson, Jake Berry, last month called for spending rules to be relaxed in order to rebalance Britain’s economy.
He told The Yorkshire Post: “Everything the Treasury has done has been done on quite a strict value for money scoring, which is quite right because we are spending taxpayers’ money and we have to spend it in an efficient way.
“But the Northern Powerhouse can be a bit more than that. Sometimes it has just got to be a leap of faith. If we don’t invest in the North, the North will never be as good as it can be.
“So, where some projects may, because areas of the North are a low wage economy, just fall below that really strict value for money scoring, which I support in the Treasury, we need the political vision to say – ‘look, this is more important, this is about transforming people’s lives across the North of England’. You can’t put that in a formula.”
Asked if he agreed with Mr Berry’s assessment, Mr Johnson said: “I wouldn’t want to dissent from whatever Jake said to you. I don’t know exactly what he said but it sounds very sensible. I am a fan of Jake and I am a fan of all Yorkshire MPs.”
Sparking speculation that Mr Berry could be set for a promotion, Mr Johnson also pledged to elevate the Northern Powerhouse brief to Cabinet level.
"There will be somebody absolutely representing the Northern Powerhouse and the interests of the North, you bet, in the Cabinet," he said.
But he stopped short of naming who would be responsible for the portfolio.
“I am not saying anything about the future composition of the Cabinet... that would come under the category of measuring the curtains,” he said.
Turning to infrastructure, Mr Johnson reiterated his commitment to the ambitious transport plan, Northern Powerhouse Rail, which would transform connectivity across the region.
He compared the £39bn scheme to London’s Crossrail, which will connect the capital from east to west when it is completed in 2021.
“I want to be the Prime Minister who does for Northern Powerhouse Rail what I was able to do for Crossrail in London,” he said.
“We need that connectivity from Hull to Liverpool. It’s not there yet. It can be done...
“Crossrail was going to be axed. It was on the chopping block and we saved it.”
He also insisted that he will not scrap the Government’s flagship rail plan, HS2, despite setting out plans for a review of the project.
He said: “I am going to ask Doug Oakervee - who is the former chair of Crossrail and who built the Hong Kong network and did lots of things of incredible things around the world - to do a six-week kicking of the tyres to see whether we can reprofile any of that spend...
“I want to be clear, that doesn’t mean I’m going to scrap HS2.
“But I want to look at ways in which we can accelerate the provision of Northern Powerhouse Rail.”
On Brexit, he said: “We got a big vote for Leave in this county and that was partly about democracy, it was partly about immigration, but it was also about feeling that it was time to bring the country together and we must be investing more in the North.”