Prior to serving in the legislature, Steinhoff taught math in Columbia Public Schools for 34 years. She is a National Board Certified Teacher. She earned the National Education Association's highest honor of Teaching Excellence, and MU's College of Education and Human Development 2023 Lifetime Achievement Award.

Steinhoff was extensively involved with Columbia NEA, where she served in many capacities, including as president from 2015 to 2021. She also served for nine years on the negotiations team. She is a volunteer with Moms Demand Action.

A graduate of Truman High School, Steinhoff obtained a bachelor's degree in Math Education, and a master's degree in Curriculum and Instruction from the University of Missouri-Columbia.

Born in St. Louis, Steinhoff now resides in Columbia with her husband. She is a proud mother and grandmother. She is a longtime member of Our Lady of Lourdes parish.