Video report by ITV News Political Reporter Shehab Khan
The prime minister held a victory rally in Sedgefield, Co Durham - for so long the seat held by former Labour leader Tony Blair - to praise people for "perhaps breaking the voting habits of generations" to put their cross down next to the Conservatives.
"And I want the people of the North East to know that we in the Conservative Party and I will repay your trust - and everything that we do, everything that I do as your Prime Minister, will be devoted to repaying that trust," he said
"And first of all what are we going to do? We're going to get Brexit done."
He said there was much more than just Brexit - including improving "our fantastic National Health Service".
Mr Johnson saw a surge in support among the former Labour heartlands, much of it apparently driven by frustration with the delay to deliver on the Brexit referendum.
The prime minister made reference on the steps of Downing Street to the fact he was conscious many people had "loaned" him their vote.
And on Saturday, he was again at pains to point out that he recognised he needed to repay that faith.
"We not the masters, we are the servants now, and our job is to serve the people of this country and to deliver on our priorities - and our priorities and their priorities are the same," he said.
Mr Johnson said the Government would be committed to spreading opportunity across the country.
"We believe that talent is evenly distributed throughout our country but opportunity is unfairly distributed," he told supporters.
"We are going to rectify that as a One Nation Conservative government, as a people's government."
He added: "We are going to recover our national self-confidence, our mojo, our self-belief and we are going to do things differently and better as a country.
"It is going to be a wonderful, wonderful time for our country. Our country will stand tall in the world."
Mr Johnson oversaw a huge victory for the Conservative Party on Thursday, sweeping into No.10 with a healthy majority of 80 as the Labour vote collapsed.
He has vowed to get Britain out of Europe by the end of January.
Jeremy Corbyn has already indicated he will not be leading the Labour party into another election.
The PM is expected to reintroduce his Brexit deal in the Commons next week following the Queen’s Speech and State Opening of Parliament on Thursday.
He has already started work on picking up relations with key European leaders, speaking by phone with German Chancellor Angela Merkel and Irish Taoiseach Leo Varadkar.
With all 650 results declared, the Conservatives had 365 seats after the election – a net gain of 67 compared to the state of the parties at the dissolution of Parliament in November.
Labour were on 203, a net loss of 42, the SNP on 48, a gain of 13, and the Liberal Democrats on 11, a loss of 10.