Sinise was at Navistar's headquarters for a cookout that kicks off ticket sales for his annual Rockin' the Troops concert.
Organizers say the shows have raised nearly $2 million. The money pays for care packages to send to troops.
"The gesture of what this means says so much to our soldiers in the field because they know that people back home remember them," said Sinise.
The Rockin' the Troops concert that features the Lt. Dan Band will be held July 17th at Cantigny Park.