Jamison, in an interview, said she was an "exuberant" person, yet she longed for peace and tranquility; but in the end, she preferred "tumultuousness coupled to iron discipline" over leading a "stunningly boring life." In her memoir An Unquiet Mind, she concluded:
I long ago abandoned the notion of a life without storms, or a world without dry and killing seasons. Life is too complicated, too constantly changing, to be anything but what it is. And I am, by nature, too mercurial to be anything but deeply wary of the grave unnaturalness involved in any attempt to exert too much control over essentially uncontrollable forces. There will always be propelling, disturbing elements, and they will be there until, as Lowell put it, the watch is taken from the wrist. It is, at the end of the day, the individual moments of restlessness, of bleakness, of strong persuasions and maddened enthusiasms, that inform one's life, change the nature and direction of one's work, and give final meaning and color to one's loves and friendships.
Jamison was born to Dr. Marshall Verdine Jamison (1916–2012), an officer in the Air Force, and Mary Dell Temple Jamison (1916–2007). Jamison’s father, and many others on his side of the family, also had bipolar disorder.
As a result of Jamison’s military background, she grew up in many different places, including Florida, Puerto Rico, California, Tokyo, and Washington, D.C.. She has two older siblings, a brother and a sister, who are three and one half years older, respectively. Jamison’s interest in science and medicine began at a young age, which her parents fostered. She worked as a candy striper at the hospital on the Andrews Air Force Base. In addition, Jamison interned at St. Elizabeths in Washington.
Jamison moved to California during adolescence and shortly after this move began to struggle with bipolar disorder. Jamison then continued to struggle in college at UCLA wanting to first become a doctor, but with her increasing manic episodes realized she could not withstand the rigorous discipline needed for medical school. She then found her calling in studying psychology. She flourished in this field and was extremely interested in mood disorders. Jamison, despite all her studying, did not realize she was bipolar until three months into her first job as a Professor of UCLA’s Department of Psychology. After finding out, she was put on lithium (medication), a common drug used to contain moods. At times she would refuse treatment because her motor skills became impaired from the medication but after a greater depression decided to continue to take lithium. Jamison even attempted to commit suicide by overdosing on lithium but was unsuccessful.
Jamison has said that she has had a near-death experience, and has written about it, saying "mental illness can trigger religious revelations and visions -- even out-of-body and near-death experiences".
Jamison is an Episcopalian, and was married to her first husband, Alain André Moreau, an artist, during her graduate school years. She then married Dr. Richard Wyatt in 1994, and they remained married until his death in 2002. Wyatt was a psychiatrist who studied schizophrenia at the National Institutes of Health. Their romance is detailed in her memoir Nothing Was the Same.
In 2010 Jamison married Dr. Thomas Traill, a cardiologist and fellow faculty member at Johns Hopkins.