Johnson will be tasked with forming the government on Wednesday and will become the country's new prime minister.
In a vote attended by party members, Johnson received 92,533 votes, while his opponent, current Foreign Secretary Jeremy Hunt, received 46,656 votes. Thus Johnson, who is sitting on the leadership seat of the ruling party, also became the country's new prime minister.
"We are going to get Brexit done, Unite the country, and defeat Jeremy Corbyn (Labour leader)," Johnson said.
Johnson, who began his political career by being elected as an MP in 2001, served two times as London mayors between 2008 and 2016.
Johnson, who was the foreign secretary for two years in Theresa May's government, had resigned on 9 July 2018.
Following the resignation of current Prime Minister Theresa Mays to Queen Elizabeth on Wednesday, Johnson is expected to travel to Buckingham Palace to take up the task of forming the new government.
May has failed to withstand pressure from intra-party opposition after her Brexit deal was rejected 3 times in parliament, resigned from the party leadership and announced she would quit the Premiership once the new leader is elected. (ILKHA)