During World War II, most of Hollywood put on a uniform. Disney built models to train pilots for their bombing runs. Actors enlisted. Ronald Reagan entered the Army enlisted reserve in 1937. Studios started cranking out patriotic films before the first bombs dropped on Pearl Harbor. When Warner Brothers released “Sergeant York,” Sen. Gerald Nye of North Dakota held hearings to accuse the studio of warmongering.

But Hollywood has been on the sidelines of America’s wars ever since. They became just stuff for backstory. Take the 1994 film “Forrest Gump,” the story of an Alabama simpleton who redeems the faith of everyone he touches, including his disgruntled former commander Lieutenant Dan, the epitome of the burned-out Vietnam vet.

“Have you found Jesus yet, Gump?” growls legless Lt. Dan to the clueless Forrest, who replies, “I didn’t know I was supposed to be looking for him, sir.”

Gary Sinise, who played the iconic Lieutenant Daniel Taylor, could never shake off the role. Even as he picked lead roles in other movies, people on the street would give a shout-out to “Lt. Dan.”

Sinise never shook off his brush with war, service and sacrifice either. Retired Marine Captain Dale Dye, who trained Gary to act like a soldier for "Forrest Gump," recalls in a new documentary that when the film wrapped, he told Sinise, “You could have done it -- you could have soldiered.”

While Sinise never served (though many in his family did), since 9/11 he has given back to our men and women in uniform and their families like almost no one else in Hollywood has, playing more than 40 USO tours and concerts. The new documentary “Lt. Dan Band: For the Common Good,” which premiers online on July 4, chronicles the band's journey from pick-up jam sessions to funding-raising concerts for veterans and first responders.

The film is a lot like the real Lt. Dan. Though it features Sinise and the band on tour, as the story progresses they fade into the background. “Lt. Dan” is really about true heroes -- fireman who lost their lives on 9/11, fighter-pilots who never came back to their wives and young kids, soldiers who beamed at having their photograph taken with a movie star -- who never lived to share that memory.

Starting on the Fourth of July, the film can be seen online at www.ltdanbandmovie.com. Part of the proceeds from the film go to the recently established Gary Sinise Foundation, which will support programs for soldiers, veterans, first responders, and their families.

Hollywood may not be back at war. But at least Lt. Dan is out there soldiering.

James Jay Carafano is Deputy Director, The Kathryn and Shelby Cullom Davis Institute for International Studies and Director, Douglas and Sarah Allison Center for Foreign Policy Studies at the Heritage Foundation.