AP
"In his address to the UN General Assembly, President Obama will lay out a broad vision of American leadership in a changing world," the official said.
The White House acknowledged that Obama's speech comes at a time of global "unease."
"He speaks at a time when there is clearly unease over a range of challenges," the official said of Obama. "And yet we have built momentum over the last several weeks, with progress on a number of fronts: We stopped the advance of ISIL; helped secure a new, inclusive Iraqi government, and built a broad coalition of countries - including five Arab nations who have joined us in strikes against ISIL targets in Syria. Meanwhile, we have launched a renewed effort to combat the Ebola outbreak, sanctioned Russia and supported a cease-fire in Ukraine, brokered a new unity government in Afghanistan, and outlined our vision for combating climate change."
Obama has repeatedly touted the partner nations who have joined the US to aid the strikes on Islamic State, which is also known as ISIS and ISIL, that began in Iraq last month and were expanded to Syria this week. At the UN, the official said he will ask other countries to join the effort and also discuss addressing the root causes that led to the group's rise.
On ISIL, the President will call on the world to join him in this effort to degrade and ultimately destroy this terrorist organization. However he will speak more comprehensively about the need to tackle the forces that give rise to ISIL - extremist ideology, sectarian conflicts and the need for more affirmative alternatives to terror," said the official.
In addition to addressing the strikes on ISIS, the official said Obama will also outline other items on the US agenda.
More broadly he will give a clear sense of the priorities for American leadership - whether its supporting Ukraine, testing whether a nuclear deal is possible with Iran, or combating climate change and disease," the official said.
Overall, the White House said Obama will present "a forceful and optimistic message of American leadership" and emphasize the need for other countries to work with the US.
"On all these issues, America acts not alone - but leading large coalitions of countries, and he will call on more nations to join us," said the official. "This will be a forceful and optimistic message of American leadership - one that recognizes the challenges we face while making it clear that we can and will overcome them."