On a day the nation honors Martin Luther King Jr., Obama placed his hand on two Bibles – King’s traveling Bible and the burgundy velvet-covered Lincoln Bible. Obama also had used the Lincoln Bible four years ago, the first to do so since it was used by Abraham Lincoln himself.

Michelle Obama smiled broadly, while even members of Congress snapped photos with their phones.

“Congratulations, Mr. President,” Roberts said just before a 21-gun salute boomed.

Singers Beyonce, James Taylor and Kelly Clarkson performed. Richard Blanco, the youngest ever inaugural poet and the first Hispanic or gay person to recite a poem at the swearing-in ceremony, read his “One Today.” Civil rights activist Myrlie Evers-Williams delivered the invocation. Carter said the ceremony showed “unprecedented diversity – from the speeches to the prayers to the singers. . . . It showed a spirit of anticipation for the next four years.”

Minutes before Obama’s oath, Vice President Joe Biden was sworn in by Associate Justice Sonia Sotomayor, the first Hispanic and fourth female judge to administer the oath.

Afterward, Obama and Biden headed to the Capitol’s Statuary Hall to dine on steamed lobster and hickory grilled bison at a luncheon attended by 200, including Supreme Court justices and congressional leaders, sitting at tables adorned with bright orange flowers. Obama was presented with a custom hand-cut crystal Lenox vase with an etching of the White House. The tradition of the luncheon dates to President William McKinley in 1897.

House Speaker John Boehner, R-Ohio, presented Obama and Biden with the flags that flew over the Capitol. “To you gentlemen, I say congratulations and Godspeed,” he said.

Later, the Obamas led an inaugural parade – featuring eight official floats, 59 groups, 9,000 people, 1,500 service members and 200 animals – the 1.7 miles from the Capitol up Pennsylvania Avenue to the White House. They sat in a reviewing stand adorned with bulletproof glass and the presidential seal in front of the White House. Most of the onlookers waved American flags and chanted “four more years,” but a handful of protesters held “God hates Obama” signs.

In the evening, the president and first lady attended two official inaugural balls, one for members of the military and another for the public.

The president danced with Mrs. Obama, wearing a custom Jason Wu ruby colored chiffon and velvet gown, to “Let’s Stay Together” sung by Jennifer Hudson.

At the commander-in-chief ball, Obama expressed “the extraordinary gratitude not just of me as your commander-in-chief but the thanks of all the American people.” He also spoke via video to members of the military on the ground in Afghanistan. “Every single day we’re thinking of you,” he said.

Erika Bolstad, Sean Cockerham, Anne-Kathrin Gerstlauer, Franco Ordonez, Maria Recio and Lindsay Wise contributed to this article.