The event was part of the Joining Forces campaign, which connects veterans with resources to help them find jobs.
The first lady announced this year's White House Christmas theme is 'Joy to All,' and talked about the tree dedicated to the military.
"This very special Joining Forces tree is covered with hand-decorated ornaments made by military children living in U.S. bases around the world," Obama said. "We have spent months and months gathering these beautiful ornaments."
Although the White House looks decorated already, the first lady said there are 54 trees throughout the mansion and many need a child's touch.
