Johnson won 92,153 votes by members of the Conservative Party On Tuesday, Reuters reported. His main rival, Foreign Secretary Jeremy Hunt, won 46,656.
He is to be sworn in as premier later in the day.
Johnson has won a reputation as the most famous personality promoting the country’s 2016 referendum on whether it should leave the European Union (EU) or continue being part of the bloc.
The public voted in favor of a departure in the vote. The government has, however, missed two deadlines to act on the results, as the Number 10 and Brussels keep failing to reach an agreement on the status of their relations post-Brexit.
In his first remarks to follow his Tory victory, Johnson said he would “get Brexit done” this October with or without a deal.
The pledge now pits London against Brussels, which demands a deal, and the parliament, which has vowed to bring down any government that could try to enforce a no-deal Brexit.
Also facing Johnson are escalated tensions with Iran following Britain’s seizure of a supertanker carrying Iranian oil in the Strait of Gibraltar off Spain on July 4. Iran has slammed the move as maritime “piracy.”
On Friday, Iranian naval forces seized a British oil tanker in the Persian Gulf after it collided with a fishing boat and refused to respond to its distress call.
Meanwhile, Iran’s Foreign Minister Mohammad Javad Zarif congratulated Johnson — whom he referred to as “my former counterpart” — on his victory but emphasized Tehran’s condemnation of the confiscation of the supertanker by “the May govt.”
The British naval forces captured the vessel on the accusation that it was carrying Iranian oil to Syria in violation of the European Union (EU) unilateral sanctions on the Arab country.