the votes polled on Saturday.
71-year-old, Dr Tony Tan, will take over from President SR Nathan at the end of this month when he retires.
Indian-origin Nathan has served two six-year terms.
Welcoming the results and election of Dr Tony Tan, Prime Minister Lee Hsien Loong said "this is the first presidential election in 18 years. It is good that Singaporeans have had the chance to vote for their next President, and to focus on what the elected President is about. I thank the four candidates for putting themselves forward."
Dr Tony Tan, a former top ranking political executive of the ruling People's Action Party (PAP), won by a thin margin of 0.34%, or 7,269 votes against its rival, garnering 744,397 votes or 35.19% of the 2.15 million votes casts yesterday.
Tan Cheng Bock, 71 and a former PAP member of parliament, received 737,128 votes or 34.85% of the votes.
A former civil servant and now a financial investment advisor Tan Jee Say, 57, received 529,732 or 25.04% of the votes in the first ever four-corner presidential election campaign.
Tan Kin Lian, 63 and a former executive of an state insurance company, lost his deposit after receiving only 4.91% or 130,931 votes.
"Voters have chosen Dr Tony Tan as our Head of State, to represent us at home and abroad, and to exercise custodial powers, including over reserves and key appointments," said the Prime Minister in a statement this morning.
"Voters faced a difficult choice between Dr Tony Tan and Dr Tan Cheng Bock. This explains why the winning margin is so narrow, and why the winner only gained slightly more than one-third of the total votes. Nevertheless, under our first-past-the-post system, the election has produced an unambiguous winner, who has the mandate to be the next President," Lee said.
The presidential candidates and Singaporeans debated the importance of the President over the last nine days of campaigning after nominations were submitted on August 17.
The debate focused on the power of President and those of the Prime Minister, the Parliament as per the country's constitution, with the government and the four candidates explaining and reasoning on the role of the Head of State.
Internet media reported Singaporeans' views on the need to have a President with a wider check on the government, then the current power to safeguard the prosperous city state's past reserves, power to protect or reject critical appointments in the civil service as well as the final decision on certain laws of the land.
Dr Tony Tan comes with the experience of having served as minister with various portfolios, being the Deputy Prime Minister and Deputy Chairman of Singapore's Government Investment Corporation.
However, he had retired from political office and resigned from the corporation to contest for the Presidency as mandatory requirement that the candidates should not be affiliated to any political party, and should have managed a corporation with assets of SGD100 million or served in an equal position in the government.