Jane Jensen joined Sierra On-Line as a programmer and writer. She initially worked on supporting roles in several games, gaining experience with the company's game engine and development process.

Jensen wrote the story and dialog for King's Quest V, a successful and popular entry in the series. This project helped her establish herself as a talented writer and designer within Sierra.

Jensen designed and wrote 'Gabriel Knight: Sins of the Fathers', a critically acclaimed supernatural mystery adventure game. This game marked her debut as a lead designer and solidified her reputation for creating compelling narratives and complex characters.

Jensen designed and wrote 'Gabriel Knight 2: The Beast Within', a sequel to 'Sins of the Fathers'. This game featured full-motion video (FMV) and further explored the series' themes of mystery and supernatural horror. The game was critically acclaimed for its innovative use of FMV and its compelling story. This cemented Jane's position as a innovative force in game design.

Jensen designed and wrote 'Gabriel Knight 3: Blood of the Sacred, Blood of the Damned', the third installment in the Gabriel Knight series. This game transitioned to 3D graphics, a significant change from the previous titles. While generally well-received, some fans felt it didn't quite capture the same magic as the earlier games.

Jane Jensen left Sierra On-Line after the release of 'Gabriel Knight 3'. The exact reasons for her departure aren't fully public, but it's understood she wanted to pursue other creative opportunities and explore different projects.