For the next 15 minutes, according to a senior aide, Obama spoke without interruption, laying out his message of why the not-guilty ruling had caused such pain among African-Americans, particularly young black men accustomed to arousing the kind of suspicion that led to the shooting death of Martin in a gated Florida neighborhood.
On Friday, reading an unusually personal, hand-written statement, Obama summed up his views with a single line: "Trayvon Martin could have been me 35 years ago."
That moment punctuated a turbulent week marked by dozens of phone calls to the White House from black leaders, angry protests that lit up the Internet and streets from Baltimore to Los Angeles, and anguished soul-searching by Obama. Aides say the president closely monitored the public reaction and talked repeatedly about the case with friends and family.
Several people who have had conversations with Obama's top aides said a president who has rarely spoken about America's racial tensions from the White House was particularly torn about appearing to force the hand of Eric H Holder Junior, the attorney general, when it comes to any investigations in the case.
The White House's original plan - for Obama to address the verdict in brief interviews Tuesday with four Spanish-language television networks - was foiled when none of them asked about it.
Instead, he appeared in the White House briefing room with no advance warning and little of the orchestration that usually accompanies presidential speeches. Obama spoke for 18 minutes, offering his own reflections and implicitly criticizing gun laws and racial profiling methods - both of which, critics say, played a role in Martin's death.
As he has before, Obama did not criticize either the conduct of the trial or the verdict, in which a jury found a neighborhood watch volunteer in Sanford, Florida, George Zimmerman, not guilty of all charges in the killing of Martin in February 2012.
But in the most expansive remarks he has made about race since becoming president, Obama offered three examples of the humiliations borne by young black men in America: being followed while shopping in a department store, hearing the click of car doors locking as they cross a street, or watching as women clutch their purses nervously when they step onto an elevator. The first two experiences, he said, had happened to him.
"Those sets of experiences inform how the African-American community interprets what happened one night in Florida," Obama said. "And it's inescapable for people to bring those experiences to bear."
For black leaders who had beseeched the president to speak out - inundating White House officials with phone calls - his remarks were greeted with a mixture of relief and satisfaction.
The Rev Jesse Jackson said Obama had no choice but to confront mounting concern among African-Americans about the Martin case and recent Supreme Court rulings on affirmative action and voting rights.
"At some point, the volcano erupts," Jackson said.
From the moment the verdict was announced Saturday night, black activists had called on Obama to express the anger and frustration of their community. The pressure only increased after he issued a carefully worded statement urging respect for the jury's decision.
"We needed this president to use his bully pulpit," said the Rev Al Sharpton, a civil rights activists and host on MSNBC, who urged Obama's advisers to have him speak out.
Martin's parents, Sybrina Fulton and Tracy Martin, said they were "deeply honored and moved" by Obama's comments. "President Obama sees himself in Trayvon and identifies with him," they said in a statement Friday. "This is a beautiful tribute to our boy."
For some black activists, however, Obama's remarks were too little, too late. Tavis Smiley, a radio host who has long been a critic of the president, said the president had chosen to "lead from behind" on race issues.
The president's advisers selected the White House briefing room as the location for Obama's remarks during the Thursday meeting, calculating that it would be less formal than a full-dress speech - but would shield him from the questions he would likely face in a longer interview about why he had waited days after the verdict to speak.
The advisers said Obama was anxious to confront the issue of race in a way that he has not since he ran for president in 2008. In a landmark speech to defuse the political storm over his Chicago pastor, the Rev Jeremiah A Wright Junior, Obama spoke about what he called "the complexities of race" in America.
As president, Obama has only periodically returned to the subject. And on the few occasions that he has, it has often been in reaction to an incident - a black Harvard professor's arrest, or Martin's death. A month after Martin was killed, Obama said, "If I had a son, he'd look like Trayvon."
The president's remarks Friday were different: more expansive, more personal and more reflective of the concerns of fellow black people. His comments mirror public opinion among African-Americans, according to polls.
A telephone poll conducted June 13 to July 5 by Gallup found that black people were "significantly less likely now than they were 20 years ago to cite discrimination as the main reason blacks on average have worse jobs, income, and housing than whites." It found that 37 percent of blacks today blame discrimination. In 1993, 44 percent said the same.
Obama has also shown more willingness to speak in personal terms. At Morehouse College in Atlanta in May, he told graduates, "Sometimes I wrote off my own failings as just another example of the world trying to keep a black man down."
His remarks Friday were also reminiscent of the tone in his speeches during his trip to Africa this month. After standing in the cell that Nelson Mandela occupied for 18 years, Obama told a South African audience, "You've shown us how a prisoner can become a president."
On Friday, Obama brought that message home, urging Americans to be honest with themselves about how far this country has come in confronting its own racial history.
"Am I wringing as much bias out of myself as I can?" he asked. "Am I judging people, as much as I can, based on not the color of their skin but the content of their character? That would, I think, be an appropriate exercise in the wake of this tragedy."