Although this intense actor was almost 30 when he made his television debut, he had been honing his craft for years on stage as a founding member of the critically acclaimed Chicago-based Steppenwolf Theater Company. In fact, his small-screen acting break, True West, which aired on PBS, was just a videotape of a production he had mounted. Sinise alternated between directing and acting before settling on the latter in the '90s, playing key supporting roles in numerous Hollywood blockbusters (Forrest Gump, Apollo 13, The Green Mile). But after a succession of flops, Sinise turned to the tube in 2004 to star in his first TV series, CSI: NY.