Despite the hardened opposition from Senate Republicans, White House officials insist there is no Plan B to hold off on Garland's nomination.
“We expect Chief Judge Garland to be confirmed in this Congress. Period," Schultz said.
News of Garland’s selection leaked out after Obama held a conference call with Democrats on the Judiciary Committee.
“We think the people should choose, as we’ve said repeatedly,” McConnell told reporters after the call.
Republicans argue an Obama pick would undoubtedly shift the balance of the court to the left and want the next president to decide Scalia's successor.
In Garland, Obama is putting forth a candidate he says is deserving of GOP support.
The 63-year-old judge has built a reputation as a moderate who is well-liked by Republicans. His professional résumé is similar to many justices already on the high court.
The judge has proven to be confirmable in a Republican-controlled Senate. The upper chamber in 1997 voted 76-23 to confirm him. Thirty-two Republicans joined the majority, seven of whom are still in office.
The D.C. Circuit has long been considered a stepping stone to the high court. Three current justices — as well as Scalia — served there previously.
Garland was a top contender for the last Supreme Court opening in 2010, which Obama ultimately filled with his then-solicitor general, Elena Kagan.
Hatch, a senior member of the Judiciary Committee, said at the time he would help Garland get confirmed if he was nominated — as Obama noted when he nominated Garland on Wednesday.
"I have no doubts that Garland would get a lot of [Senate] votes,” Hatch, a former chairman of the panel, told Reuters then. “And I will do my best to help him get them."
Hatch on Sunday called Garland a "fine man" and suggested Obama should nominate him.
"[Obama] could easily name Merrick Garland, who is a fine man," the senator told the conservative news site Newsmax
"He probably won’t do that because this appointment is about the election," he added. "So I’m pretty sure he’ll name someone the [liberal Democratic base] wants."
"I do hope they will do their constitutional duty and give President Obama's nominee a meeting, a hearing and a vote. He's doing his job this morning," he said. "The Republicans should do theirs from this point forward."
Trumka said he had initially heard Obama would select someone else but added his labor federation will support Garland.
“He’s a great judge. I had not heard Merrick is going to be appointed,” he said. “Merrick Garland’s a great judge, and we would support him.”
Garland’s experience could be appealing to members on both sides of the aisle.
He clerked for Supreme Court Justice William Brennan, who was appointed by Republican President Dwight Eisenhower but went on to lead the court’s liberal wing, and Second Circuit Court of Appeals Judge Henry Friendly, another Eisenhower appointee under whom Chief Justice John Roberts also clerked.
During his service as a federal prosecutor, he oversaw cases involving the 1995 Oklahoma City bombing and the Unabomber, Ted Kaczynski.
Despite his lengthy résumé, Garland is somewhat of a surprise pick for Obama, who has valued racial, ethnic and professional diversity in his past judicial picks.
Garland is a white male who would not add religious diversity to the bench — he is Jewish. At 63, he would be one of the oldest people ever to be confirmed to the high court. Like five other current justices, Garland graduated from Harvard.
Garland’s lengthy paper trail built up over almost two decades on the federal bench could also give Republicans ample opportunity to find objectionable views.
Republicans argued Wednesday that it would be relatively easy to oppose Garland because McConnell and Grassley were on record against him nearly 20 years ago.
A senior GOP aide argued that Obama’s decision to pick the oldest judge on his short list shows that he doesn’t have much hope of getting the pick confirmed by the Republican-controlled Senate.
Alexander Bolton, Jordain Carney and Jesse Byrnes contributed.
Updated at 1:08 p.m.