Jean Frances Tatlock was born in Ann Arbor, Michigan, the daughter of John Strong Perry Tatlock, a prominent professor of medieval literature at the University of Michigan, and Marjorie Fenton Tatlock. Her upbringing within an academic environment undoubtedly shaped her intellectual curiosity and fostered a lifelong love of learning.

Tatlock's early life exposed her to progressive social and political ideas. Her family's intellectual milieu encouraged critical thinking and engagement with contemporary issues. This environment helped form her own deeply held beliefs, especially concerning social justice and economic equality.