At the Summit of the Americas in this island capital, Mr. Obama signaled he was ready to accept Cuban President Raul Castro's proposal of talks on issues once off-limits for Havana, including the scores of political prisoners held by the communist government.
Mr. Obama also shook the hand of Venezuela's Hugo Chavez (a leader who once likened the president's predecessor to the devil) and casually exclaimed, "Como estas?"
Responding to the overture, Chavez walked over to President Obama at a meeting, patted the president on the shoulder and handed him a book, "La Venas Abiertas de America," [or, "The Open Veins of Latin America"]. The book by Eduardo Galeano is an essay on five centuries of exploitation of Latin America by North American and European interests.
An English paperback edition is available on Amazon.
CBS News White House correspondent Mark Knoller caught Secretary of State Hillary Clinton, sitting behind Mr. Obama, laughing at Chavez's stunt.
Saturday was the first full day of meetings in the two-island nation of Trinidad and Tobago, just off Venezuela's coast. Mr. Obama was taking part in a series of plenary sessions, group gatherings and one-on-one meetings that the White House hoped to squeeze into a busy schedule. He hoped to make time for individual sessions with leaders from Canada, Colombia, Peru, Haiti and Chile, aides reported.
At his first meeting with South American leaders, President Obama waited several minutes while security officers and members of the media pushed noisily into the room. Somebody accidentally hit a light switch, prompting Mr. Obama to ask: "Who turned off the lights, guys?"
He said he hoped events would go more smoothly during the meeting where he said he would talk to the leaders about energy, security and other topics. "I have a lot to learn and I'm very much looking forward to listening," the president said.
In an opening speech to the 34-nation gathering on Friday, the president promised a new agenda for the Americas, as well as a new style.
Mr. Obama also extended a hand to a leader Ronald Reagan spent years trying to drive from power: Nicaragua's Daniel Ortega. The Sandinista president stepped up and introduced himself, U.S. officials reported.
Yet soon after, Ortega, who was ousted in 1990 elections that ended Nicaragua's civil war but who was returned to power by voters in 2006, delivered a blistering 50-minute speech that denounced capitalism and U.S. imperialism as the root of much hemispheric mischief. The address even recalled the 1961 Bay of Pigs invasion of Cuba, though Ortega said the new U.S. president could not be held to account for that.
"I'm grateful that President Ortega did not blame me for things that happened when I was three months old," President Obama said, to laughter and applause from the other leaders.
But perhaps the biggest applause line was his call for a fresh start in relations between Washington and Havana.
"I know there's a longer journey that must be traveled to overcome decades of mistrust, but there are critical steps we can take toward a new day," he said.
On Tuesday, Mr. Obama ordered an easing of travel and remittance restrictions for Americans with relatives in Cuba. Within hours, Castro - who took over from his ailing brother Fidel a year ago - responded with an offer of talks on "everything" that divides the two countries.
The White House welcomed the offer, but suggested actions would be better, such as releasing some of Havana's scores of political prisoners.
Added Mr. Obama: "I am not interested in talking for the sake of talking. But I do believe that we can move U.S.-Cuban relations in a new direction."
Cuba became a dominant issue even though the summit was taking place amid the worst global downturn since the Great Depression.
To Latin American nations reeling from a sudden plunge in exports, Mr. Obama promised a new hemispheric growth fund, an initiative to increase Caribbean security and a new regional partnership to develop alternative energy sources and fight global warming.
But most of all, he offered an end to old hemispheric arguments.
"I didn't come here to debate the past," President Obama said. "I came here to deal with the future ... We must learn from history. But we can't be trapped by it."