No, he never was.
But after I remember fram a interview I have seen with him, he said that he have family that are/was serving.
I belive his brother in-law. Was in the military.
Gary Sinise is third generation Italian.However, his mother's maiden name is Alsip, which is English. In fact, the name Alsip is connected with the early 11th Century Anglo-Saxon name Allsop; meaning...