He said Saturday he is not daunted or dismayed by a vote delaying approval of the new Brexit deal, and said there will be no new negotiations with the EU.
He says he still believes he can command "overwhelming" support for the new Brexit divorce plan and will introduce the required legislation to make that happen.
Johnson says he is not compelled by the law to negotiate any further with the EU.
British lawmakers have voted to postpone a decision on whether to back a Brexit deal with the European Union, throwing a wrench into government plans to leave the bloc at the end of this month.
At a special session of Parliament intended to ratify the deal, lawmakers instead voted 322-306 to withhold their approval until legislation to implement the agreement has been passed.
The vote is a major blow to Prime Minister Boris Johnson and means he has to ask the EU to delay Britain's departure. Parliament previously passed a law compelling him to do that if a deal had not been passed by Saturday.
The move is intended to ensure the U.K. can't crash out of the EU without a deal on the scheduled Oct. 31 departure date.
The government still hopes it can pass the needed legislation by the end of the month so the U.K. can leave on time.
Former Prime Minister Theresa May, whose Brexit deal was rejected by Parliament three times, says she is backing the agreement struck by her successor Boris Johnson.
May told lawmakers she had a "distinct sense of deja vu" as Parliament debated whether to back Johnson's EU divorce deal. She resigned in frustration after lawmakers repeatedly threw out her Brexit agreement.
Johnson's deal is similar to May's in some ways but contains a different arrangement for maintaining an open Irish border.
May said Parliament should pass the deal and let Britain leave the EU on Oct. 31. She said "people want certainty in their lives. . If you want this country to move forward then vote for the deal today."
Tens of thousands of anti-Brexit protesters are marching through London as lawmakers debate Prime Minister Boris Johnson's new European Union divorce deal.
Protesters, many wearing blue berets emblazoned with yellow stars symbolizing the EU flag, poured out of subway trains and buses for the march to Parliament Square on Saturday.
In one side street, a group of demonstrators with bells strapped to their legs and wielding sticks performed a traditional English morris dance and chanted: "Morris, not Boris!" to cheers from onlookers.
One of the dancers, Kate Fisher, says "demos that are fun and joyful are more effective."
Elsewhere, the mood was less cheerful.
Sarah Spoor, who cares for her two children with disabilities, choked back tears as she said she is "distraught" at the prospect of Britain leaving the EU.
Thousands of Brexit opponents are gathering in central London to call for Britain to remain part of the European Union.
The crowds are planning to converge on Parliament Square as legislators are voting on Brexit departure plans put forth by Conservative British Prime Minister Boris Johnson.
Many carried signs calling for a halt to the Brexit process that started with a 2016 referendum in which British voters narrowly backed taking Britain out of the 28-nation bloc.
Protester Bruce Nicole, a vicar from Camberley southwest of London, said the Brexit deal would harm Britain.
He says "I fervently believe that we should remain in the EU." He adds "I am British but I am also European. I don't believe the current deal offers any benefits at all."
Opposition leader Jeremy Corbyn has told Parliament that the Brexit deal on which lawmakers are voting risks jobs, rights, the environment and the health service.
The Labour Party leader told Parliament Saturday that Prime Minister Boris Johnson's new deal is substantially worse than the one it replaces, which was voted down three times.
Corbyn says it removes protection for workers' rights and the environment and replaces them with empty promises. He says it would also reduce Britain's commitment to fighting climate change.
He also warns it would hurt British manufacturing.
British Prime Minister Boris Johnson has told Parliament that his new Brexit deal can heal the rift in British politics and unite warring factions.
He used a rare Saturday session to plead with lawmakers to back the new plan.
He says it would "take back control" of Britain's borders, fishing and trade and preserve the gains of the Good Friday agreement that helped end violence in Northern Ireland.
Johnson faces a close vote on his plan with opposition parties determined to block it.
Prime Minister Boris Johnson's plan to get Parliament to approve his Brexit deal with the European Union has been thrown into doubt.
Lawmakers will first vote on whether to withhold approval until legislation to implement the agreement has been passed. That would bring another law into play that would force Johnson to seek a Brexit delay from the European Union.
House of Commons Speaker John Bercow said would allow a vote on an amendment that essentially puts the vote on the deal off until another day.
Those behind the amendment say it will remove the risk that the U.K. could stumble out of the bloc without a deal on Oct. 31 because the law is not in place.
The vote is due later Saturday.
Prime Minister Boris Johnson's Brexit plan faces what is expected to be an extremely tight vote as Britain's Parliament prepares for its first Saturday session since the 1982 Falklands war.
At stake is a new divorce plan agreed between the British government and the other 27 European Union nations at a summit Thursday.
Johnson hopes for success in getting a fractious Parliament to back the deal after his predecessor, Theresa May, failed three times to get lawmakers behind her plan.
Johnson does not have a parliamentary majority but he is hoping to woo some opposition Labour Party lawmakers to his side.
He said in The Sun newspaper on Saturday that a vote for the plan would bring a "painful chapter in our history" to an end.