The strategy, which includes sending 30,000 more U.S. troops to Afghanistan by next summer, is based on a very deliberate process, Mullen said in an interview with American Forces Press Service.
"It (the decision-making process) has allowed us to explore the breadth and depth of this enormously complex challenge, and in the end, the president has made the decision to add these 30,000 troops," he said.
The increase will give Army Gen. Stanley McChrystal, top commander of U.S. and NATO forces in Afghanistan, what he needs over the next 12-18 months plus the flexibility to deploy them were needed, Mullen said.
Obama considered military leaders' points of view when determining his strategy, Mullen said.
"I've been at the table in these discussions from beginning to end, and my voice has been heard," he said. "I'm very comfortable with that."
Obama's decision gives McChrystal the forces he needs to execute the strategy, Mullen said.
"We're all confident in that, and I'm actually confident that we can succeed at this endeavor," he said. "The key goal here is to reverse the momentum of the Taliban."
The strategy calls on Afghan President Hamid Karzai to help grow Afghan security forces rapidly, provide good governance on all levels, and "to really take responsibility for their own country," Mullen said. "It's a big challenge."
The president's strategy also addresses requirements of U.S. civilian agencies and seeks assistance from NATO allies. Mullen said he expects to hear from NATO partners soon and is "cautiously optimistic we'll see additional support from NATO."
Notable deaths of 2014 [PHOTOS]