Chair, NBCUniversal Cable Entertainment Group, Comcast, 66
Despite a rapidly changing media landscape, Hammer’s networks churn out hits. Mr. Robot, which launched on USA Network last year, is one of the most popular shows on TV. It’s also critically acclaimed, garnering six Emmy nominations. But that’s just one series. Hammer, the highest-ranked woman at NBCUniversal, oversees 10 cable networks, including USA, Bravo, Syfy, and E!, and 137 original shows, with a collective 129 million viewers. She also spearheaded NBCUniversal’s August deal for the broadcast and cable rights to the Harry Potter franchise.