Mary LaCoste earned her B.S. from the University of South Alabama in Secondary Education in 1994. She holds teaching certifications in both English and history. LaCoste earned her M.Ed from the University of West Alabama in Library Media in 2015 and her Instructional Leadership certification from the University of West Alabama in 2019.  She taught middle school English for eight years and high school English for five years. She was the Library Media Specialist at Baker High School for four years.

Mary LaCoste is from Mobile and has three children, Emily, Brant, and Molly. Her hobbies include walking her dog, Scout, working in her yard, and spending time with friends and family.