Little is known about her history. After finishing school, she met Bannon's father (which name is unknown) and Earl Davis in the military academy possibly as a nurse for military enlistment checkup. She married him and gave birth to would-be Captain Mark Bannon a few years later.
During Vietnam War, her husband and Earl fought in the jungles against the NVA and VC while taking care of young Mark. After the war, her husband was KIA during the Tet Offensive possibly leaving her grieved.Earl (who became bitter over his friend's death) then married her and became the stepfather of Mark Bannon who isn't so fond of him.
World War IIIEdit
During the Invasion of Seattle,Harriet and Earl had settled far away from the invasion possibly Tennesse, USA. She always received calls from her son but its always Earl to pick up the phone.She missed her son very much but for Earl,he isn't because he doesn't like spoiled brats for defending the USA from the "damn commies".
After Captain Bannon and the remnants of Charlie Company were perished in a nuclear blast along with the Soviet invaders in Cascade Falls,she received a final message from her son about that he will do something right and she grieved for his death while that cranky Earl doesn't. Her fate is unknown.