Obama aimed a message squarely at his critics who say his reform proposals will cost too much but did not provide a detailed plan for where the money comes from.
"This is legislation that will be paid for. It will not add to our deficits over the next decade. We will find the money through savings and efficiencies within the health care system -- some of which we've already announced," he said.
Obama started off the news conference with a 10-minute prepared statement that addressed Iran, energy legislation and health care.
He issued his strongest statement yet on the recent violence in Iran, deploring the loss of innocent civilian life and condemning what he called "unjust actions" taken by the government there.
"The United States and the international community have been appalled and outraged by the threats, the beatings and imprisonments of the last few days," he said. "I strongly condemn these unjust actions, and I join with the American people in mourning each and every innocent life that is lost."
Amid criticism from Republicans who say he has not offered strong enough backing of the protests of the contested Iranian election, Obama today repeatedly stressed that the United States respects Iran's sovereignty and does not want to meddle it its affairs but acknowledged the "courage and dignity" of the Iranian people.
Obama called energy legislation making its way through the House "historic" and said it will "transform the way we produce and use energy in America."
Obama pinned the legislation's price tag on the "the polluters who currently emit the dangerous carbon emissions that contaminate the water we drink and pollute the air we breathe."
"It is legislation that will finally spark a clean energy transformation that will reduce our dependence on foreign oil and confront the carbon pollution that threatens our planet," he said.
The president also stood by his statement that the nation's unemployment will end up going over 10 percent and said that jobs are a lagging indicator of economic recovery.
He said he does not see a need for a second stimulus package because he wants to see how effective the first one can be, which he credited with stabilizing the economy.
"In the absence of the stimulus, I think our recession would be much worse. It would have declined," he said. "Without the Recovery Act, we know for a fact that states, for example, would have laid off a lot more teachers, a lot more police officers. And a lot more firefighters."
Obama continues to enjoy high approval ratings, but his policies may not be as popular. An ABC News/Washington Post poll showed that 65 percent of Americans approve of the president's job performance. But less than half of those polled, 47 percent, feel the country is not headed in the right direction, making it the first time since Obama's election that views of the country's course have not improved.
Americans also seem to be losing faith in the $787 billion stimulus. The number of people who believe the federal stimulus will help the economy fell to 52 percent, down from 59 percent in late April, and 19 percent said they feel it would hurt the economy.