Patricia "Pat" Jameson was the late governor of Hawaii who established the Hawaii Five-0 Task Force as a means of cleaning up the islands of Hawaii which had become overrun with crime and corruption.
In spite of her good deeds, Jameson was later exposed as a corrupt politician who was in league with the crime boss, Wo Fat (2010) with Wo Fat himself later killing her and framing Lieutenant Commander Steve McGarrett (2010) for the crime.
Much of Jameson's background and past remains unknown but it is presumed that prior to becoming the Governor of Hawaii, she was also a politician who made many powerful friends and allies.
Hawaii Five-0 Season 1
After some reclutance, Steve accepted and became the new leader of the unnamed Task Force with Detective Sergeant Danny Williams (2010), Detective Lieutenant Chin Ho Kelly (2010) and Officer Kono Kalakaua (2010) eventually joining the team. Jameson returned in Nalowale (episode) where she requested that the newly Hawaii Five-0 team help determine who had killed Amanda Reeves, the daughter of Ambassador Michael Reeves and his wife, Sarah Reeves.
When McGarrett confronted Governor Jameson in her office, he was tasered by Wo Fat who in turn shot Jameson twice in the chest, killing her instantly before leaving the gun in McGarrett's hand and fleeing the scene, making it look like McGarrett had killed the Governor.
After Jameson's death, Governor Samuel Denning replaced her as the governor of Hawaii while McGarrett was jailed for supposedly killing Jameson but was eventually found innocent of any involvement in Jameson's murder.
In spite of her good deeds, Jameson's legacy could be considered a double-edged sword as while she was devoted to ensuring that the islands of Hawaii were free from corruption and all traces of crime, ironically, Jameson herself was corrupt, having gotten into business with dangerous criminals.
Despite that, the people of Hawaii, unaware of the truth chose to see Jameson as a hero and presumably saw her death as a great loss to the community as well as the world of Hawaiian politics.