Nomination of 63-year-old Garland - the chief judge for the US Court of Appeals for the District of Columbia Circuit - fills the Supreme Court seat left vacant by the sudden death of conservative icon justice Antonin Scalia last month.
The centrist judge, who hails from Obama's home town of Chicago, currently serves as the chief judge on the US Court of Appeals for the District of Columbia - a post he took over in 2013.
"Garland would bring integrity, modesty and even- handedness and excellence to (the) Supreme Court," Obama said as he described the nominee as someone who is widely recognised as a legal luminary.
The President called the long-time jurist and former prosecutor as "one of America's sharpest legal minds".
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Garland has served on the DC appellate court since 1997, when he was nominated to the bench by the then President Bill Clinton. He was confirmed with a 76-23 vote.
White House officials said that the former prosecutor "has more federal judicial experience than any other Supreme Court nominee in history".
The nomination comes at a time of bitter political divide when it would be tough for Obama to get through his choice of the judge and sets the stage for an intense showdown by Senate Republicans who have maintained that Obama should not choose Scalia's successor, with less than a year left for his presidency.
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Justice Garland, in his brief remarks, said: "If the Senate sees fit to confirm me to the position for which I have been nominated today, I promise to continue on that course."
He said the trust that justice will be done in US courts without prejudice or partisanship is what, in a large part, distinguishes this country from others.
"He or she must put aside his personal views or preferences and follow the law -- not make it. Fidelity to the Constitution and the law has been the cornerstone of my professional life. And is the hallmark of the kind of judge I have tried to be for the past 18 years," he said.
Obama said throughout Garland's jurisprudence runs a common thread, a dedication to protecting the basic rights of every American, a conviction that in a democracy, powerful voices must not be allowed to drown out the voices of everyday Americans.
People respect the way he treats others, his genuine courtesy and respect for his colleagues and those who come before his court, he added.
Well aware that the Republican leadership is pre- determined to oppose his nomination, Obama urged the Republican leadership in the Senate not to play politics with the Supreme Court.
"It's supposed to be above politics. It has to be. And it should stay that way.
"To suggest that someone who has served his country with
honour and dignity, with a distinguished track record of delivering justice for the American people might be treated, as one Republican leader stated, as a political pinata. That can't be right," Obama said.
"I chose a serious man and an exemplary judge, Merrick Garland. Over my seven years as president, in all my conversations with senators from both parties in which I asked their views on qualified Supreme Court nominees, and this includes the previous two seats that I had to fill, the one name that has come up repeatedly from Republicans and Democrats alike is Merrick Garland.
"Now, I recognise that we have entered the political season, or perhaps these days it never ends, a political season that is even noisier and more volatile than usual," he said.
The Republican leadership in the Senate immediately made its intentions clear that it would not confirm Obama's nomination to the US Supreme Court.
"This issue is not about any single nominee - it's about the integrity of the Court," argued Senator John McCain.
"With less than a year left in a lame-duck presidency and the long-term ideological balance of the Supreme Court at stake, I believe the American people must have a voice in the direction of the Supreme Court by electing a new president," he said.