Obama and Xi opened a weekend of secluded talks with mutual pledges to consider the other nation's interests, but the world's two largest economies have been at loggerheads on a vast array of issues from trade to cybersecurity.
Their laid-back summit, stripped of the normal pageantry, was called in a bid to build a personal bond between Xi, who has just assumed full power as Chinese leader, and Obama, who is beginning his second term.
Welcoming Xi to the sumptuous Sunnylands retreat under the blazing California sun, Obama voiced hope that the two countries "can forge a new model of cooperation between countries based on mutual interest and mutual respect."
Obama sought to reassure Xi that the United States is not trying to contain China, a frequent charge in Beijing as the US administration pursues a "pivot" strategy of stepping up its focus on Asia.
"It is in the United States' interests that China continues on the path of success because we believe that a peaceful and stable and prosperous China is not only good for the Chinese, but also good for the world and the United States," Obama said.
But Obama wasted no time in hitting a key theme of the visit from the US side -- complaints of an alleged Chinese Internet spying effort targeting American military and commercial secrets and intellectual property.
Obama said both sides should "work together" on issues such as cybersecurity, North Korea's defiant nuclear program and climate change.
The president also pledged that the United States would raise human rights, a longstanding concern of US lawmakers and campaigners who deplore China's harsh treatment of democracy advocates, religious groups and ethnic minorities.
"History shows that upholding universal rights will ultimately be a key to success and prosperity and justice," Obama said.
Xi, like Obama wearing a dark suit with an open collar and no tie, mirrored his host's theme of a new approach, saying: "The vast Pacific Ocean has enough space for two large countries like the United States and China."
"We're meeting here today to chart the future of China-US relations and draw a blueprint for this relationship," Xi said, next to aides in identical business casual outfits.
Xi, who is expected to lead China during a decade in which it will overtake the United States as the world's largest economy, reiterated his frequent if occasionally vague call for world powers to think differently about relations.
"We need to think creatively and act energetically, so that working together, we can build a new model of major country relationship," Xi said.
The 59-year-old leader holds credibility as the son of one of China's founding revolutionaries and speaks in a confident, free-flowing style, a shift from the stilted formality of his predecessor Hu Jintao that frustrated the White House.
The two leaders had not been expected to meet until the G20 summit in Russia in September. But both sides, sensing uncertainty seeping into a complicated and often difficult relationship, saw value in an earlier encounter.
"Our decision to meet so early I think signifies the importance of the US-China relationship," Obama said.
"It's important not only for the prosperity of our two countries, and the security of our two countries, but it's also important for the Asia-Pacific region, and thus for the world."
China has signaled that it too is a victim of cyber espionage. In troublesome optics for Obama, the summit comes as he faces criticism over revelations that the United States has run a massive Internet and telephone surveillance program for security purposes.
The White House rejected charges that the scandal weakened Obama's hand and instead said that the row showed how the United States holds vibrant discussions on individual rights.
"This is a pretty good illustration of the type of conversation we want to have about respecting civil liberties and protecting the constitutional rights of the people that you govern," White House spokesman Josh Earnest said.
In a bid to ensure cyber security does not overshadow this summit, the two sides have already announced they will hold working group level talks on the issue in July.