Tom Kalinske was the president of Sega of America during the Genesis years. Under his leadership, Sega moved from 1% market share in 1990 to 50% in 1994. Sega-16 interviewed him in July of this year:
linky linkyThe interview was pretty eye-opening for me, Kalinske describes how his success in the US led to the the Sega of Japan - Sega of America hate (which persists to this day), and provides some good reasons why the Saturn failed in the US.