U.S. President Barack Obama has unveiled his choice for the next justice in the U.S. Supreme Court.

Praising her "rigorous intellect," Obama tapped federal appeals Judge Sonia Sotomayor for the Supreme Court on Tuesday, making her the first Hispanic in history picked for the role.

"She is an inspiring woman who I believe will make a great justice," Obama said at a press conference in the White House's east room.

"She brings with her more experience on the bench than anyone currently serving on the United States Supreme Court had when they were appointed," he said.

President Barack Obama and Vice-President Joe Biden applaud federal Appeals Court Judge Sonia Sotomayor, after the president announced her as his nominee to the Supreme Court on Tuesday during a ceremony at the White House. (Alex Brandon/Associated Press)

If confirmed by the Senate, Sotomayor, 54, would succeed retiring Justice David Souter.

Sotomayor is a self-described "Newyorkrican" who grew up in a Bronx housing project after her parents moved to New York from Puerto Rico.

She has dealt with diabetes since age eight and lost her father at age nine, growing up under the care of her mother in humble surroundings. As a girl, inspired by the Perry Mason television show and Nancy Drew novels, she knew she wanted to be a judge.

A graduate of Princeton University and Yale Law School, a former prosecutor and private attorney, Sotomayor became a federal judge for the Southern District of New York in 1992.

Obama had said publicly he wanted a justice who combined intellect and empathy — the ability to understand the troubles of everyday Americans.

Sotomayor has presided over more than 450 cases during her tenure as a judge, Obama noted, including a landmark 1994 ruling that helped end the Major League Baseball strike that year.

"There are some who think Judge Sotomayor even saved baseball," Obama joked.

Bipartisan appeal

Democrats hold a large majority in the Senate, so barring the unexpected, Sotomayor's confirmation should be assured.

But official reaction from Republicans in Washington has thus far been muted.

"Supreme Court vacancies are rare, which makes Sonia Sotomayor's nomination a perfect opportunity for America to have a thoughtful discussion about the role of the Supreme Court," Republican National Committee chairman Michael Steele said in a statement.

"Republicans will reserve judgment on Sonia Sotomayor until there's been a thorough and thoughtful examination of her legal views," he said.

If approved, she would join Justice Ruth Bader Ginsburg as the second woman on the current court.

As a judge, she was first appointed by George H.W. Bush, then named an appeals judge by Bill Clinton in 1997.

"It is a testament to her that she was nominated by a Republican and promoted by a Democrat," Obama said.

Calling the nominating the "most humbling honour" of her life, Sotomayor vowed to uphold the rule of law as what she called "the foundation of our human rights."

"I am an ordinary person who has been blessed with extraordinary opportunities," she said.

With files from The Associated Press