They are of different generations and from different Americas, their political lives separated by philosophy and circumstance. But Monday at the White House, President Obama and former president George H.W. Bush and their families united under the banner of volunteerism.

At an afternoon ceremony in the East Room of the White House, Obama and Bush honored a retired couple from an Iowa farming town who have helped deliver free meals to hungry children around the world.

The couple received the 5,000th Points of Light award. The awards were established by Bush in 1989 to celebrate the power of individuals to spark change and improve the world. In his remarks, Obama paid a special and personal tribute to Bush — his oldest living predecessor — and said he and other presidents have striven to follow Bush’s lead in encouraging national service.

“Mr. President, I’m one of millions of people who’ve been inspired by your passion and commitment,” Obama said. He added, “You’re such a gentleman, such a good and kind person, and we are surely a kinder and gentler nation because of you.”

Bush, who at 89 has been battling health problems, appeared frail but in good spirits as he was pushed onstage in a wheelchair by a Marine. Returning to the White House, he said, was “like coming home for Barbara and me.”

Obama spoke warmly about Bush’s longevity, noting that he jumped out of an airplane on his 85th birthday. “After he left the White House, he kept going and going and going,” the 44th president said of the 41st. “In between skydiving and other activities, he kept going. . . . This is somebody who’s not going to slow down anytime soon.”

Bush and Obama honored Floyd Hammer and Kathy Hamilton of Union, Iowa, who a decade ago were set to retire until they took a trip to Tanzania and saw children dying of malnutrition. They founded a nonprofit group, Outreach, that delivers food to the world’s hungry.

The award’s name, like the Points of Light charitable foundation begun during Bush’s presidency, is a reference to Bush’s 1989 inaugural address, in which he likened the nation’s community groups to “a thousand points of light.”

Neil Bush, chairman of the Points of Light foundation, choked up as he spoke about his father’s legacy of volunteerism.

“He may not be parachuting anymore, but he’s taken on a new hobby — he’s trying to be a style setter. ‘GQ man,’ we’re calling him, instead of ‘41,’ ” Bush said of his father, who sported red-and-white-striped socks.

Obama has been a proponent of volunteerism as well, launching a National Day of Service connected to both of his inaugurations. On Monday, he announced a federal task force to identify ways that the government and the private sector can work together on national service projects.

First ladies Michelle Obama and Barbara Bush were present for the ceremony. Beforehand, the two families shared a private lunch in the Red Room, a grand parlor on the first floor of the White House.

Monday’s events mark a continued thawing of relations between Obama and the Bushes.

In 2011, Obama warmly welcomed the Bush family to the White House as he awarded the Medal of Freedom — the nation’s highest civilian honor — to the elder Bush, patriarch of a political dynasty. Obama and George W. Bush also met last month in Tanzania, where Obama praised his predecessor’s AIDS relief program.

Then last week, the younger Bush delivered a rare public address on policy matters and called on fellow Republicans to support comprehensive immigration reform, which is the centerpiece of Obama’s second-term domestic agenda.