Mullen, chairman of the Joint Chiefs of Staff since 2003, spoke at a town hall meeting in the Capitol Theatre before an audience of more than 750, including 350 local high and middle school students.
Mullen said he has been speaking at similar meetings "to hold a conversation with the country so we can learn more about each other."
While Chambersburg is the smallest community he visited, it has one of the biggest audiences, he said.
Mullen, who was introduced by U.S. Rep. William Shuster, R-9, was invited to speak by the Greater Chambersburg Chamber of Commerce and the Scotland Landing Foundation.
Mullen abandoned the podium to stand alone, relaxing at center stage as if speaking to smaller, more personal audience. He was candid and took time to fully answer questions.
A graduate of the U.S. Naval Academy in Annapolis, Md., Mullen said he is proud to lead a military of "extraordinary men and women from all over the country who have made and want to make a difference."
Many have paid the ultimate price, he said.
"Their average age is the early 20s. That has always been the case, and they share their burdens proudly," he said.
Mullen said those sent to Iraq and Afghanistan serve multiple deployments, sometimes four and five times, and for as long as 15 months. The military is improving the rotation cycles so they serve a year in country and a year home.
"We hope to make that one year in and two years back so they're home longer than they're deployed." he said.
The change in Iraq has been "breathtaking," because of the sacrifices by Americans who served there, he said.
"It's not about violence anymore, it's about politics now."
Answering a question about Afghanistan from a member of the audience, Mullen said: "We lost some great young men and women there last year, and this year will be a very tough."
There are 30,000 Afghan soldiers in training, but the country still needs legitimacy in its government that people there can support, he said.
An audience question came from Zunaira Mobasher, a junior at Chambersburg Area Senior High School. She was, until six months ago, living in Pakistan. She asked Mullen how the people of Pakistan feel about the U.S. presence there.
"We're not very popular in Pakistan," he said.
It's a challenge when they ask if the U.S. military is leaving or staying.
"We have left them in the lurch many times."
An extremely high number of Pakistanis have been killed, Mullen said.
"They've sacrificed a lot. Their own military has been without relief."
The real problem for America lies on the Pakistan/Afghan border, where al-Qaida is harbored, he said.
A retired Army colonel and West Point graduate in the audience asked for help for a wounded soldier from Afghanistan with 100 percent disabilities who his family is taking care of. The military is not doing enough for the soldier, he said.
The colonel said there is a "disconnect" between the military and the Veterans Administration on deciding the level of disability the soldier is qualified for that should have been settled before he was discharged.
"It should not be up to the family to take care of him, it should be up to the military," the colonel said.
"There are too many cases like you describe," Mullen said. "We're trying to move faster with the disability evaluation."
The country, military and VA, as well as the community, have to do more to meet the needs of servicemen and women and their families, he said.
Mullen said he tries to be meet with families waiting for the remains of loved ones at Dover Air Force Base, at burials at Arlington National Cemetery and in military hospitals. His wife, Deborah, who was in Chambersburg Thursday, meets often with wounded veterans and their families, he said.
The nonprofit Scotland Landing Foundation is trying to help veterans and their families transition from the military to civilian life. The foundation's first priority is serving wounded veterans and surviving family members of those who died in the line of duty.
It's headquarters will take over the buildings and facilities at the former Scotland School for Veterans' Children in Scotland, Pa. Donations can be made through the Franklin County Development Corp. or www.scotlandlandingfoundation.org