Former civil servant Carrie Lam was by far the clear winner, receiving 777 votes from Hong Kong's 1200 strong election committee, more than double received by her two rivals combined.
John Tsang, who had been the public's favourite, received 365.
The third, and most liberal candidate, retired judge Woo Kwok-hing received only 21 votes.
Appearing before her supporters, Carrie Lam vowed to focus on the economy, provide jobs, and reform government agencies.
"Here with humanity, I stand as chief executive-elect of the Hong Kong Special Administrative Region of the People's Republic of China. I'm ready to begin a new chapter in our journey together."
The 59 year old is the daughter of a Shanghainese ship worker, and a mother who never received a formal education.
Growing up in a cramped apartment shared by four siblings and several families-- Ms Lam went go on to study sociology at the University of Hong Kong-- before taking part in social activism, and eventually politics.
But despite the new leadership, the fact that Hong Kong's 7.3 million people have no say in choosing their leader remains a source of tension.
Just moments after Carrie Lam took to the stage, a group of activists appeared and began chanting "I want universal suffrage."
They carried yellow umbrellas, a symbol of the 2014 pro-democracy protests that led to widespread violence.
But Ms Lam carried on unfazed, promising to unite the people.
"Hong Kong, our home, is suffering from quite a serious divisiveness and has accumulated a lot of frustrations. My priority will be to heal the divide and to ease the frustrations, and to unite our society to move forward."
That could prove difficult, given the lack of widespread public support for her.
Outside, protesters vowed to keep up the fight against what they call an election committee whose loyalty lies with China rather than the people.
Ka Lun-- the district counsellor for Hong Kong's Yuen Long area-- has condemned Ms Lam, and the committee who elected her.
"These last five years have been a nightmare for Hong Kong people. And Carrie Lam openly admitted at the very beginning of her election scheme, that she will continue with the current system handed down by the current CE (Chief Executive Leung Chun-ying). Now what we can expect is continuing this nightmare for another five years. This is the worst scheme for us, the worst news for us today in Hong Kong."
Since Hong Kong returned to Chinese rule in 1997, Beijing has gradually increased control over the territory.
This comes despite China promising freedoms and autonomy under the formula of "one country, two systems".
But Hong Kong Election Committee member Starry Lee insists Ms Lam will do the right thing by the people-- and the city as a whole.
"Lam will continue upholding the "One Country, Two systems" principle. And she will focus on the economy. This is very important because Hong Kong's competitiveness is declining."
Ms Lam has said that unless social tensions are eased-- electoral reform talks are unlikely to happen anytime soon.
She will formally become Hong Kong's chief executive on the first of July.
