"Today, I am nominating Chief Judge Merrick Brian Garland to join the Supreme Court," Mr. Obama said from the White House Rose Garden with Garland and Vice President Joe Biden standing alongside him.
After seeking the advice of Republicans and Democrats in Congress, constitutional scholars and advocacy groups, the president said he selected a nominee who is "not only one of America's sharpest legal minds," but someone who has "a spirit of decency, modesty, integrity, even-handedness and excellence."
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Special Report: President Obama to nominate Merrick Garland to U.S. Supreme Court
Garland, 63, has served as the chief judge on the U.S. Court of Appeals for the District of Columbia for the last three years. He has served on the D.C. appellate court since 1997, when he was nominated to the bench by former President Bill Clinton. He was confirmed by the Senate in a 76-23 vote.
Over that 19-year period on the D.C. circuit, the president said Garland "has earned a track-record of building consensus as a thoughtful, fair-minded judge who follows the law."
Mr. Obama argued that is it "rare" to find someone who is liked by members of both political parties and alluded to comments from Sen. Orrin Hatch, R-Utah, and Chief Justice John Roberts in which they praised Garland.
"Chief Justice John Roberts once said, 'Anytime Judge Garland disagrees, you know you're in a difficult area,'" Mr. Obama said.
Garland, who the president said will travel to Capitol Hill to meet "one-on-one" with senators on Thursday, spoke briefly about his nomination.
"This is the greatest honor of my life," other than his wife agreeing to marry him, Garland said as he choked up. "I am grateful beyond words for the honor you have bestowed upon me."
A number of Democrats watched the announcement from the Rose Garden including Senate Majority Leader Harry Reid, D-Nevada, and Senate Judiciary Committee Ranking Member Patrick Leahy, D-Vermont.
The president said Garland has spent years "protecting the rights of others." As valedictorian of his high school class, a student speaker who first delivered a fiery critique of the Vietnam War was silenced by parents attending their graduation. The president said Garland "tossed aside his prepared remarks and delivered a passionate, impromptu defense of our First Amendment rights."
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U.S. President Barack Obama stands next to Judge Merrick Garland (C) of the United States Court of Appeals as his nominee for the U.S. Supreme Court as Vice President Joe Biden (L) joins in at the Rose Garden of the White House in Washington March 16, 2016. REUTERS/Jonathan Ernst REUTERS
This is not the first time Garland, who hails from President Obama's home in Chicago, has been considered for a Supreme Court seat. Following the 2010 retirement of Justice John Paul Stevens from the Supreme Court, Garland's name was also floated for the nomination. The seat was eventually filled by Associate Justice Elena Kagan, then the Solicitor General.
Before his career as a judge, Garland held several positions in the public and private sectors. Garland worked as a prosecutor in the Department of Justice's criminal division. While at the DOJ, he served as principal associate deputy attorney general, where he supervised investigations into the 1995 Oklahoma City bombing and Unabomber Ted Kaczynski. From 1985 to 1989, and then again from 1992 to 1993, Garland served as a partner in the law firm of Arnold and Porter in Washington, D.C. Garland served as a clerk for Supreme Court Justice William Brennan from 1978 to 1979.
Garland's appointment is a bipartisan appeal for President Obama, considering the judge's moderate history and support from senators across the aisle. In 1997, Sen. Hatch assisted in securing Garland's confirmation to the appeals court. The White House pointed out in a background memo that in 2010, Hatch viewed Garland as "a consensus nominee" for the court before Mr. Obama selected Elena Kagan.
"I have no doubts that Garland would get a lot of [Senate] votes," Hatch said at the time. "And I will do my best to help him get them."
But Hatch, in a phone interview with CBSN Wednesday morning before the president's announcement, said that even if Garland was the president's choice, the Senate is "not going to move or even discuss the qualifications of any nominee until after the presidential election."
Of his previous support of Garland, Hatch said, "Being on the circuit Court of Appeals is quite a bit different from being on the Supreme Court. It's not about the person, it's not about the president. It's about protecting the integrity of the court."
Seven sitting Republican senators voted to confirm Garland when he was nominated to the appellate court in 1997: Sen. Dan Coats, R-Indiana; Sen. Susan Collins, R-Maine; Sen. Thad Cochran, R-Mississippi; Sen. Jim Inhofe, R-Oklahoma; Sen. John McCain, R-Arizona; Sen. Pat Roberts, R-Kansas; and Hatch.
Five of the "no" votes from 1997 are also still in the Senate: Sen. Majority Leader Mitch McConnell, R-Kentucky; Sen. Mike Enzi, R-Wyoming; Sens. Richard Shelby and Jeff Sessions, R-Alabama; and the current chairman of the Sen. Judiciary Committee, Sen. Chuck Grassley, R-Iowa.
Garland graduated magna cum laude from Harvard Law School in 1977. Before that, he earned his undergraduate degree, graduating summa cum laude, from Harvard in 1974. Garland has also taught antitrust law at the university and once served as the school's Board of Overseers president.
He faces an uphill battle in Congress. The Senate must confirm his nomination, but the Republican majority has already ruled out considering it. They have said they will refuse to hold confirmation hearings or votes until the next president is sworn in next January.
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Sen. Orrin Hatch: I wouldn't hold hearing for Merrick Garland
Mr. Obama has called on Senate Republicans to fulfill their constitutional responsibility to confirm his nominee and ensure that the court is complete with nine members. But GOP leaders have offered little to no wiggle room as they wish to make the 2016 presidential election a referendum on the future of the Supreme Court.
"I have fulfilled my constitutional duty," the president said Wednesday. "Presidents don't stop working in their final year; neither should a senator."
Meanwhile, critical cases that the high court will hear this cycle hang in the balance. And if rulings result in a 4-4 decision, the lower court's ruling would stand.
Garland's appointment comes just over a month after Scalia's sudden death at a resort in Texas at the age of 79. Nominated by President Ronald Reagan, he was the longest-serving member on the Supreme Court.
CBS News' Jan Crawford, Margaret Brennan and Grace Lamb Atkinson contributed to this report.