Greg Daniels served as the senior series showrunner for the first four seasons of the series and developed the British series for American television. He then left the position with fellow Office writer Michael Schur. Paul Lieberstein and Jennifer Celotta were named the series showrunners for the fifth season. Celotta left the series after the sixth season and Lieberstein stayed on as showrunner for the following two seasons. He left the showrunner spot after the eighth season. Daniels returned to the showrunner position for the ninth and final season.
Other executive producers include cast members B. J. Novak and Mindy Kaling. Kaling, Novak, Daniels, Lieberstein and Schur made up the original team of writers. Kaling, Novak and Lieberstein also serve multiple roles on the series, as they play regular characters on the show, as well as write, direct and produce episodes. Credited with twenty-four episodes, Kaling is the most prolific writer on the staff.
Main Cast
Source: https://en.wikipedia.org/wiki/List_of_The_Office_(U.S._TV_series)_characters