He danced the tango, lauded Argentine soccer star Lionel Messi and made amends for U.S. complicity in one of the country's darkest eras.
President Obama prepared to leave Argentina on Thursday night, having endeared himself to much of the population.
Experts said the two-day visit has burnished the U.S. image here and given a boost to the country's recently elected president, Mauricio Macri, who hopes to implement market-friendly reforms after a dozen years of leftist populism under his predecessors. It is a shift underway in several Latin American countries.
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Obama is taking advantage of the "retreat of populist regimes to re-launch a presence in the region," political analyst Carlos Pagni wrote Thursday in the newspaper La Nacion. "He has chosen Macri as his ally in this play."
Typical of the polls published this week was one by Giacobbe & Associates that found 57% of Argentines supported the Obama visit while 19% opposed it.
Still, resentment against the U.S. lingers for what many Argentines see as its support for the military junta that ruled Argentina from 1976 to 1983 and killed an estimated 30,000 people.
Obama, who has promised to release classified documents from that era, wrapped up his official agenda with a stroll alongside Macri through Memorial Park, where monuments are studded with the names of the dictatorship's victims. The two leaders cast white flowers into the river where military threw the bodies.
"The United States is reflecting over what happened," Obama said in a brief statement after the tour. "I know that controversy exists over the U.S. role during that period. It's something we are working on."
But two prominent human rights groups, Grandmothers of Plaza de Mayo and Mothers of Plaza de Mayo, declined Obama's invitation to participate in Thursday's event.
In scattered protests, leftist groups also voiced their opposition to Argentina's plan to pay investors for its 2002 bond default, a settlement that Macri hopes will restore international confidence in its economy.
For his part, Obama seemed to relish the local culture.
He danced the tango with his wife at a state dinner Wednesday and said he enjoyed the national drink, mate.
In a town hall meeting with young entrepreneurs Wednesday, he talked about Messi and Manu Ginobili, an Argentine who plays for the San Antonio Spurs basketball team.
The Obamas and their two daughters departed Buenos Aires on midday Thursday for Bariloche in Patagonia, where they will spend the afternoon on a private tour of the exclusive resort area. The were scheduled to arrive back in Washington on Friday.
Special correspondents D'Alessandro and Kraul reported from Buenos Aires and Bogota, Colombia, respectively.