A longtime media executive, Greenstein is president of Sirius Satellite Radio, where he oversees the company's programming efforts.

Greenstein started out as a mergers-and-acquisitions lawyer before transitioning into the entertainment industry and joining Miramax in 1993. One of Harvey and Bob Weinstein's closest confidantes at the studio, Greenstein helped negotiate big deals for the Weinstein brothers (such as the one that brought Oscar-winner The English Patient to Miramax) and became so powerful that he was nicknamed "the third Weinstein brother." In 1997, Greenstein left to become co-president of October Films, which was purchased by Barry Diller in 1999 and turned into USA Films. Greenstein was named chairman and spent three years at the studio before stepping down in 2002 after clashing with its new owners. He joined Sirius shortly thereafter as President and Chief Content Officer.

Greenstein's biggest deal, of course, was the 2004 blockbuster that brought Howard Stern to Sirius. The deal made sense for both parties. Stern was tired of the increasingly intrusive FCC regulations on commercial radio, and Sirius needed a major star to put them on the map. Greenstein has gained a reputation as an aggressive, often ruthless executive and negotiator. "He will go anywhere, knock down any wall, call anyone, do anything, and I'm an admirer of that," Diller once said. Author Peter Biskind was less kind in Down and Dirty Pictures, his 2004 book about Miramax, calling Greenstein a "terrier on speed," "hatchet man," and "crime scene laundryman who wipes the blood off the walls." [Image via Getty]