"I will try my best to the greatest degree I have and carry out my civic duties as best I can", the newly elected president told reporters as he left parliament after the vote.
The development is coming a week after ex-president Htin Kyaw, stepped down from the position owing to health reasons.
Myanmar's military ruled the country for a half-century during which it was accused of widespread abuses before partially handing power to a civilian government in 2016. His two opponents, Henry Van Thio and Myint Swe, received 18 and 211 votes respectively.
Although Win Myint holds the post of president, Aung San Suu Kyi is the country's de-facto leader in her post as state counselor, which she has declared is "above the president". But she was barred from becoming president by a constitutional provision drafted specifically against her, which prohibits a person with a foreign spouse or children with foreign nationality from becoming president.
But the role has been a largely ceremonial one since Suu Kyi rose to power after her party won a supermajority in parliament in 2015.
Having been both a member of the NLD's Central Executive Committee and speaker of the lower house for two years shows Win Myint holds the skills to be president, said Win Zaw, a lower house lawmaker from the party.
"I will try my best to fulfill my duty to the people", Win Myint told reporters as he waved his hands before rushing away from parliament by vehicle.
Trump signs spending bill, blasts Congress
Many House members are or were in NY at the funeral for Democratic Congresswoman Louise Slaughter, who passed away last week. We can hire hundreds of new CBP officers. "We chose to use our leverage to help this bill pass", Pelosi said.
Activists have been frustrated with his reluctance to abolish a controversial online defamation law that has seen dozens of people face charges for Facebook posts critical of the government or military.
The new president fought alongside Ms Suu Kyi during the 1988 democracy movement which was violently quashed by the military junta.
Win Myint was born in the Irrawaddy Delta in 1951.
The key criteria for this job was loyalty to Aung San Suu Kyi.
He joined the NLD when it was founded around pro-democracy protests in 1988.
"He is good at both legislation and administration and I assume that is a good thing", said NLD upper house representative Nwe Nwe Aung.
In 1990, Win Myint won a seat in parliament for the NLD in an election that was quickly nullified by the military. After winning a seat again in the 2015 general election, he was appointed as speaker of the Pyithu Hluttaw, or Lower House.