Judge Terri B. Zion was born in Charlotte, North Carolina, to the late R.F. and Margaret Boyd. She is one of seven children, including her twin sister. Her family moved to Chester, South Carolina, in 1960, where her father worked for Ruth's Salads, while her mother assumed the role of housewife.

Judge Zion's husband, John, is retired from South Carolina Department of Health and Environmental Control. She and her husband are active members of Orr's Baptist Church in Chester.

Judge Zion attended public school in Chester and graduated from Chester Senior High School in 1973. She is a 1975 graduate of Winthrop College in Rock Hill, South Carolina, and holds an Associate of Science degree in Business.

Judge Zion served in the local Democratic Party for many years. She began working for the Chester County Probate Court in 1975 as a probate clerk under Judge E.K. Hardin. She served as Deputy Probate Judge from 1991-2018 under Judge Lois H. Roddey.

Judge Zion was elected Chester County Probate Judge in the November 2018 election and took office in January 2019.