WASHINGTON  Sonia Sotomayor took the judicial oath on Saturday, becoming the first Hispanic and the third woman to serve on the Supreme Court.

At just past 11 a.m., Chief Justice John G. Roberts Jr. administered a pair of oaths to her in two private ceremonies at the Supreme Court building, completing her ascent to a life-tenured position as the nation’s 111th justice  the first to be nominated by a Democratic president since 1994.

In the first ceremony, she took the standard oath affirmed by all federal employees, swearing to “support and defend the Constitution of the United States against all enemies, foreign and domestic.” Only the chief justice, Justice Anthony M. Kennedy, Justice Sotomayor’s immediate family, Judge Robert Katzmann of the United States Court of Appeals for the Second Circuit, members of the chief justice’s staff and a court photographer attended this ceremony. Her mother, Celina Sotomayor, held a Bible for the ritual.

They then walked to the court’s East Conference Room for the judicial oath, joined by several dozen friends and family members, where Justice Sotomayor swore to “administer justice without respect to persons, and do equal right to the poor and to the rich, and that I will faithfully and impartially discharge and perform all the duties incumbent upon me” under the Constitution and laws of the United States.