Showrunner
1. “Showrunner” is a term originating in the United States television industry referring to the person who is responsible for the day-to-day operation of a television series—although such persons are generally credited as an executive producer or supervising producer.
Traditionally, the showrunner is the creator or co-creator of the series, but this is not always the case. In long-running shows, often the creator of the show moves on, and day-to-day responsibilities of showrunning falls to other writers or writing teams.
Source: Wikipedia