Under the guidance of the Second Hokage, Tobirama Senju, Koharu and her teammates, Hiruzen and Homura, completed numerous missions and became close friends. When Hiruzen became the Third Hokage, Homura and Koharu became his councilors. With their years of experience and knowledge and their unending effort to make Konohagakure a better place, they eventually gained similar respect and social status as the Hokage himself.

She holds the belief that the group is more important than any of its individual members. Because of this, she always tries to do what she thinks is the best for Konoha, even if it goes against the Hokage's or her opinion. She is also quite demure, but does not let this stop her from voicing her opinion. In fact, despite this, she is one of the few people able to put the Fifth Hokage in her place when she oversteps her authority. Like Homura, she is more militant than the Hokage she served under have been, and sometimes leans more to Danzo's point of view.