Just after 8 a.m., Associate Justice Sonia Sotomayor administered to Biden the oath of office at the Naval Observatory, his official residence. Sotomayor is the first Hispanic and fourth female judge to administer an oath.
Biden was sworn in using the Biden family Bible, which is five inches thick and has a Celtic cross on the cover. Biden used the Bible each time he was sworn in as a U.S. senator and when he was first sworn in as vice president in 2009.
Just prior to reading the oath, the Rev. Kevin O'Brien offered a prayer, per the request of Biden and his family.
"Gracious God, at this moment in our history, we ask your blessing on your servant, Joseph, as he renews his sacred pledge to his country. Amid all the complexities of our world, a world so beautiful but also broken, give him a share of your wisdom so that he can know what is good and give him the courage to always do what is right," he said.
"Walk close by him so that he can do justice and to labor tirelessly for a more just and gentle world. Empower him to be a voice for those without a voice, for those on the margins, those so easily overlooked, for you will judge us all by how we care for the least among us."
Biden personally selected Sotomayor to administer the oath.
"It's an incredible honor to have Associate Justice Sonia Sotomayor swear me in," Biden said in a statement prior to the ceremony. "I believed strongly that she would make a great Justice, and it was one of the greatest pleasures of my career to be involved in her selection to the court."
Sotomayor left immediately after administering the oath. "She has to leave right now," Biden told the 120 guests gathered at the event. He said she was due in New York. "So I apologize, we are going to walk out, her car is waiting, so she can catch a train I hope I haven't caused her to miss," he said.
Biden and his family and friends celebrated mass prior to taking the oath.
After the ceremony, Biden joined Obama at Arlington National Cemetery for a traditional wreath-laying ceremony.
Obama and Biden will take their public oaths Monday in front of the Capitol before a crowd on the National Mall.