Outlining the strategy in an interview with The New York Times, Obama said the conditions would not be narrowed for "outliers like Iran and North Korea" that have violated or renounced the Nuclear Non-Proliferation Treaty.
"I'm going to preserve all the tools that are necessary in order to make sure that the American people are safe and secure," Obama told the newspaper.
Under the new strategy, the United States would be committed not to use nuclear weapons against non-nuclear states that are in compliance with the treaty or with their non-proliferation obligations, according to the Times and a US official who confirmed the details of the strategy.
Another exception would allow an "option to revise" the commitment not to use nuclear weapons if there were a biological weapons attack and if a country's development or proliferation of bioweapons posed a risk of a devastating attack.
The strategy would also reject the development by the United States of any new nuclear weapons but that would be coupled with increased investments in the management of the nuclear stockpile.
Obama's conservative critics say his approach so far has been naive and could endanger US national security.
The Obama administration plans to formally roll out its Nuclear Posture Review on Tuesday.
The much-anticipated announcement on the size and role of the US nuclear weapons stockpile is aimed at building momentum before Obama signs a landmark arms control treaty with Russia in Prague on Thursday and hosts a nuclear security summit in Washington next week.
The Nuclear Posture Review is required by Congress from every US administration. But Obama set expectations high after he vowed to end "Cold War thinking" and won the Nobel Peace Prize in part for his vision of a nuclear-free world.
Obama said last month the new plan, delayed by months of internal deliberations, would "reduce the number and role of nuclear weapons in our national security strategy, even as we maintain a safe, secure and effective nuclear deterrent."
He now faces the challenge of lending credibility to his arms control push while not alarming allies under the US defense umbrella or limiting room to maneuver in dealing with emerging nuclear threats from Iran and North Korea.
Obama told the Times he was convinced Iran was on a course that "would provide them with nuclear weapons capabilities."
He also said he wanted to see the United Nations adopt a sanctions resolution "that has bite" to pressure Iran over its nuclear program.
The review is a test of Obama's effort to make controlling nuclear arms worldwide one of his signature foreign policy initiatives. It is also important because it will affect defense budgets and weapons deployment for years to come.
The strategy was developed after a lengthy debate among Obama's aides and military officials over whether to declare that the United States would never be the first to use nuclear weapons in a crisis but would act only in response to attack.