"When Justice Sotomayor put her hand on that Bible and took that oath ... we came yet another step to the more perfect union that we all seek," Obama told a White House reception.
The ceremony was packed with family and friends of Sotomayor, who has become the first Hispanic and third woman in the Supreme Court's 220-year history. Lawmakers, issue advocates, Hispanic community leaders and others who helped shepherd her confirmation through the Senate also watched jubilantly as she appeared with the president for remarks.
"While this is Justice Sotomayor's achievement, the result of her ability and determination," Obama said, "this moment is not just about her. It's about every child who will grow up thinking to him- or herself, `If Sonia Sotomayor can make it, then maybe I can too.' "
Following Obama at the lectern, Sotomayor spoke emotionally about how she persevered through a modest background and difficult young life to propel herself to the highest court in the land. She grew up in public housing projects in South Bronx, N.Y., before getting an Ivy League education and starting her legal career.
"It is our nation's faith in a more perfect union that allows a Puerto Rican girl from the Bronx to stand here now," she said, a line that earned her huge applause and a standing ovation from the audience.
"I am struck again today by the wonder of my own life and the life we in America are so privileged to lead," Sotomayor said. "I am deeply humbled by the sacred responsibility of upholding our laws and safeguarding the rights and freedoms set forth in our Constitution. I ask not just my family and friends, but I ask all Americans to wish me divine guidance and wisdom in administering my new office."
Two fellow members of the Supreme Court -- Justices Ruth Bader Ginsburg and John Paul Stevens -- attended the event. Obama joked that they and their colleagues were surely ready to give Sotomayor "some good tips."
Sotomayor was sworn in over the weekend. She was a federal judge for 17 years before Obama nominated her in May to replace retired Justice David Souter. The president and his wife, Michelle, hosted a White House reception after the remarks.
Obama didn't attend her Saturday swearing-in at the Supreme Court, administered by Chief Justice John Roberts, out of what aides said was deference to the court's independence.
Still, Obama wasn't going to miss the opportunity to publicly trumpet what is expected to win him considerable chits with the politically potent Hispanic community. So he scheduled the unusual White House event -- which came several days after her official joining of a court that is a separate branch of government and which frequently rules on cases critical to the administration.
Sotomayor, meanwhile, has no time to rest from the grueling confirmation process. The court's rookie and its second-youngest justice, she is moving to Washington from New York and getting to work studying and hiring clerks immediately so that she'll be ready when the court hears arguments beginning Sept. 9 in an important and complicated case about money in campaigns.
The entire court will convene the day before for a formal ceremony to welcome Sotomayor and the new court term formally begins Oct. 5.