Both of her parents come from multigenerational Mormon families, but Sheffield's father was eventually excommunicated from the official LDS Church.

[4][5] Sheffield's childhood was marked by her father's financial dysfunction and abuse, as well as the challenges of having two older brothers with schizophrenia; she left home before starting university.

Sheffield worked as a credit risk manager at Goldman Sachs and bond analyst at Moody's Investors Service and testified before the U.S. Congress as an expert witness on economic policy issues.

She is the author of a 2024 memoir, Motorhome Prophecies: A Journey of Healing and Forgiveness, published by Hachette Book Group.

[15] She was subsequently baptized in the Episcopal Church in Manhattan under the spiritual guidance of Presiding Bishop Michael Curry.