Instead, voters stripped the Conservatives of their parliamentary majority.
Joint chiefs of staff Nick Timothy and Fiona Hill formed part of May's small inner circle and were blamed by many Conservatives for the party's lackluster campaign and unpopular election platform, which alienated older voters with its plan to make them pay more for long-term care.
The resignations of Timothy and Hill, on whom May has been heavily reliant since her previous job at the interior ministry, will be a personal blow. Their influence had increasingly angered senior ministers.
British Prime Minister Theresa May speaks watched by her husband Philip in 10 Downing street, London, as she addresses the press Friday, June 9, 2017 following an audience with Britain's Queen Elizabeth II at Buckingham Palace w.
Graham Brady, who chairs the influential 1922 committee of Conservative lawmakers, said there was no public appetite for a second election after May's party failed to win a majority in Thursday's vote.
Both Downing Street and the DUP issued statements late Saturday saying talks over a deal to prop up the government would resume next week amid concern among more liberal Conservatives about May hitching her wagon to the right-wing Northern Irish party.
Closer Ties With the EU?
A Downing Street spokesperson said: "The Prime Minister has tonight spoken with the DUP to discuss finalising a confidence and supply deal when Parliament returns next week".
Defence secretary Michael Fallon said the government was not looking at a formal coalition but would seek assurances that the DUP would vote with Mrs May "on the big things" such as the budget, defence issues and Brexit.
An online petition in objection to the Tories and DUP forming a minority government has gathered more than 300,000 signatures.
London's neutrality is key to the delicate balance of power in Northern Ireland, which was once plagued by violence over Britain's control of the country.
Some Tories, including the party's Scottish leader Ruth Davidson, are unhappy about a deal with the DUP because of the party's opposition to gay marriage and abortion and other policy clashes with the Conservatives. It was a humiliating outcome after an election that May had meant to strengthen her ahead of the Brexit push.
"For instance, if London were to stay in the customs union, then it would not have to renegotiate all trade agreements", he told the Frankfurter Allgemeine Sonntagszeitung newspaper.
Formal exit talks between the United Kingdom and the 27 other European Union members were due to start June 19. But Elmar Brok, a German conservative and the European Parliament's top Brexit expert, told the Ruhr Nachrichten newspaper that the talks would now be more complicated.
Tory MP Sarah Wollaston said on Twitter before the deal was announced that she would protect LGBT rights, support the right for women to choose and would oppose any teaching of creationism in schools.
May was interior minister for six years before taking over from David Cameron in the political chaos that following last June's Brexit referendum.
Former Treasury chief George Osborne - who was sacked by May a year ago - called May a "dead woman walking", and opposition leader Jeremy Corbyn said he was ready to contest another election at any time. The narrow majority secured by the deal means parliamentary votes will be on a knife edge as the prime minister cannot afford for even a handful of her own Tory MPs to oppose her.
When asked about her position, he said: "That remains to be seen".
May had repeatedly ruled out the need for a new election before changing her mind.
Meanwhile, Labour leader Jeremy Corbyn, fresh from his party's strong showing, continues to put pressure on the weakened Conservatives.