Speaking at a celebration of the anniversary of Kennedy's inauguration, Obama told an audience at the Kennedy Center "something about that day -- Jan. 20, 1961 … feels immediate, feels new and urgent and exciting."
However, he said much has changed in the interim.
"The world is very different now than it was in 1961," Obama said. "We face new trials and new uncertainties, from our economy to our security. We have a politics that can often seem too small for the hardships at hand. So meeting these tests won't be easy. But we cannot forget, we are the heirs of this President, who showed us what is possible."
The president also acknowledged the death this week of Sargent Shriver, a Kennedy brother-in-law who Obama said "embodied the spirit of the New Frontier as well as anybody."
Shriver, who was the first director of the Peace Corps in 1961, died Tuesday.
Members of Kennedy's original White House staff gathered in Washington Thursday to observe the anniversary. The staffers met for lunch at a Constitution Avenue restaurant that overlooks the Capitol where Kennedy was sworn, a release issued by the reunion organizers said.
Kennedy drew his staff from people who worked with him when he served in Congress or on the presidential campaign trail, the release said. At least 40 of the 1961-63 White House staff are alive, with 25 living in the Washington area.