Mildred Middleton began her eighty year career as an educator at the age of eighteen in a one room schoolhouse in rural Carroll County. She attended Iowa State Teachers College (ISTC) where she earned a Bachelor of Science degree in 1943. While at ISTC she was tapped to serve as a Junior Supervisor to work with pre service educators at the ISTC Campus School. After graduation she was recruited to teach in an experimental program through the University of Wisconsin in Janesville, Wisconsin.
In 1949 Mildred moved back home to Coon Rapids, Iowa; transitioning from classroom teacher to a supervisory position; Mildred served as Supervisor of Elementary Education in the Carroll County Schools. She received her M.S. degree in Curriculum Development from Drake University in 1951.
In 1958 Mildred moved to Cedar Rapids, Iowa where she served as Coordinator of the Language Arts Curriculum. She earned a specialist degree in Reading from the University of Chicago in 1959. She retired from the Cedar Rapids School District in 1980, but she did not retire from the field of education. During her tenure with the Cedar Rapids Schools, Mildred wrote a series of spelling books, Improving Spelling Performance, which was used throughout this country and in Canada. After her retirement from full time employment, Mildred traveled the country conducting workshops for educators on the use of the spelling series.