The Brexit hardliner, a former London mayor, on Tuesday won the votes of 92,153 members of the ruling party, while his rival, Foreign Minister Jeremy Hunt, won 46,656, BBC reported.
Johnson is set to become prime minister on Wednesday, after Theresa May formally steps down.
In his victory speech, according to Financial Tribune, the 55-year-old said his campaign message had been to "deliver Brexit, unite the country and defeat [opposition Labour leader] Jeremy Corbyn - and that is what we are going to do".
"Do you look daunted? Do you feel daunted? I don't think you look remotely daunted to me," Johnson told party members at the Queen Elizabeth ll conference center in London. "We are going to get Brexit done."
Joey Jones, former spokesman for Prime Minister Theresa May, told Al Jazeera that Johnson remained a divisive figure in large parts of the UK.
"I wondered if we might see a different Boris Johnson in this particular speech. A bit more sober, with the mantle of power and prime ministerial authority descending on to him," he said.