One on each side, Obama and Clinton held the hands of Ethel Kennedy, widow of Robert F. Kennedy, as they made their way up the stairs at Arlington National Cemetery. First lady Michelle Obama and former Secretary of State Hillary Rodham Clinton joined the two presidents to place a wreath near the eternal flame that marks Kennedy's gravesite.
Obama and Clinton placed their hands over their hearts as a bugler played "Taps" near an American flag at half-mast. Obama made no public comments, but greeted Kennedy relatives gathered to honor his legacy ahead of the 50th anniversary of his assassination on Friday.
The daylong tribute began earlier at the White House, where Obama bestowed the Presidential Medal of Freedom on prominent Americans including Bill Clinton and Oprah Winfrey. Kennedy established the modern version of the medal, but was assassinated two weeks before he planned to honor the first group of recipients.
"Today, we salute fierce competitors who became true champions," Obama said, pausing to speak in personal terms about each of the recipients and their contributions to society.
The leaders honored ran the gamut from sports and entertainment to science and public service. Mrs. Clinton, Chelsea Clinton and film director Steven Spielberg were among those gathered in the East Room of the White House to watch the ceremony.
Turning to the former White House inhabitant, Obama said that Bill Clinton's presidency had been only the start of his work to improve the world, crediting his post-presidency humanitarian works as helping to save or improve the lives of hundreds of millions around the world.
"I'm grateful, Bill, as well, for the advice and counsel that you've offered me, on and off the golf course," Obama said to chuckles. "And most importantly, for your lifesaving work around the world, which represents what's the very best in America."
As a teenager, Bill Clinton shook hands with Kennedy the summer before the assassination when he and other high school students in the Boys Nation program went to Washington.
Obama said the late Sally Ride, the first American woman in space, didn't just break the stratospheric glass ceiling, "she blasted right through it."
"Young girls need to see role models, she said. You can't be what you can't see," Obama said. "Today our daughters, including Malia and Sasha, can set their sights a little bit higher because Sally Ride showed them the way."
Receiving the award for Ride, who died last year, was Tam O'Shaughnessy, who was introduced as Ride's life partner.
The president made a point of highlighting those who had overcome additional obstacles and stigmatization because they were gay, black, female or Asian. He noted that early in her career, Oprah's bosses suggested she change her name to something more relatable.
"I got the same advice," Obama said.
Kennedy established the modern version of the medal, but was assassinated by Lee Harvey Oswald in Dallas on Nov. 22, 1963, two weeks before he planned to honor the inaugural group of recipients. Hundreds of noteworthy figures have since received the medal.
In the evening, Obama plans a speech on Kennedy's legacy of service at a dinner at the Smithsonian's National Museum of American History attended by current and past medal recipients, including baseball's Hank Aaron, astronaut Edwin "Buzz" Aldrin, singer Aretha Franklin, former Federal Reserve Chairman Alan Greenspan, activist Jesse Jackson and former Secretary of State Henry Kissinger.
Kennedy's grandson, Jack Schlossberg, is to introduce Obama at the dinner. Other Kennedy relatives are expected to attend, including Robert Kennedy's daughter Kathleen Kennedy Townsend and former diplomat Jean Kennedy Smith, a former medal recipient and John F. Kennedy's only surviving sibling.
Friday marks 50 years to the day since Kennedy was slain while riding in an open car in a motorcade during a visit to Dallas. Obama plans to meet privately at the White House on Friday with leaders and volunteers from the Peace Corps program, also established by Kennedy.
The Clintons' presence at the eternal flame where Kennedy is buried was sure to spark speculation about whether Obama has a favorite in the 2016 race to succeed him.
Every move by former Secretary of State Hillary Clinton is being scrutinized for signs of whether she'll run. Vice President Joe Biden, another potential candidate, attended only the White House medal ceremony.