Donald Trump on his visit to the United Kingdom last week said Johnson would make "a great prime minister".
During his speech, Johnson repeatedly praised May for her remarks at Lancaster House in early 2017, when she said that Britain would seek a clean break from the EU.
He said Britain would end up stuck in a "miserable limbo" under the Chequers plan for future links with the European Union that prompted him to quit.
"It is not too late to save Brexit", Johnson told parliament in his resignation speech on Wednesday.
He said European leaders and the financial markets reacted positively to her statement but 'we never actually went to Brussels and turned it into a negotiating offer.' Mr Johnson added: 'We burned through negotiating capital.
"We have time, we have changed tact once and we can change again", he said.
In the last few days, the Prime Minister has reneged on promises made to the European Union in terms of the "Irish backstop" and supported amendments which have undermined her own Brexit White Paper, published only last week.
He signalled that "the problem is not that we've failed to make a free trade agreement, the problem is that we haven't tried".
"If we get distracted by individual amendments to individual pieces of legislation ... then I think we get dragged into an unnecessary debate that wastes a lot of time and energy", Foreign Minister Simon Coveney told state broadcaster RTE.
And he said Britain should be "great independent actors" on the world stage, not "rule takers".
EU Issues $5 Billion Antitrust Fine for Android Abuses
Google has built a massive business of banner and videos ads, thanks largely to its central role on Android devices. The ecosystem carries all the properties needed for a fair competition - "rapid innovation and lower prices".
He said: "The margin is closing on these votes and we will keep at it".
Over a year ago, in an article for the Western Mail, I warned that when the crunch point comes, the House of Commons would face paralysis on Brexit.
But May admitted that some aspects of the customs arrangements plan she has devised might not be ready by the end of 2020.
"A very well delivered speech from Boris but it is hopeless to expect Mrs May to deliver on any of it", said Mr Farage.
But 12 Conservatives broke ranks to back the customs union measure, even though Tory whips told would-be rebels that there would be a confidence vote if it passed - potentially resulting in the collapse of Mrs May's administration.
"Failure to keep our promise to the electorate will nearly certainly lead to the catastrophe of Jeremy Corbyn becoming prime minister and I can not sit back and allow that to happen", he wrote.
His comments reflect numerous concerns that have been expressed by the pharma industry, which has invested heavily in the United Kingdom as the EMA has been headquartered in London for the past two decades.
When Johnson announced his intent to speak, some commentators wondered if his address might be something akin to the 1990 resignation speech by Geoffrey Howe that preceded the downfall of Margaret Thatcher as prime minister.
But he says her government is "damaged" by giving in to what he calls a 'faction led by Jacob Rees-Mogg'.