Mary M. Knight was born Mary Miranda Dunbar in Southern Michigan in 1854.  She attended high school in Eaton Rapids, Michigan and began her career as an educator at the age of 16.  After completing an apprenticeship by teaching several terms, she moved with her family to Huron, South Dakota, where she continued teaching.  At age 22 she returned to Eaton Rapids and married another educator, Marcus F. Knight on June 29, 1876.  She and her husband had known each other since high school.  The Knights remained in Michigan until 1890 when they decided to move to Shelton, Washington. 

Mary immediately started teaching in Shelton, where she remained for five years before moving to Bellingham, Washington, where she lived for four years.  In Bellingham, both Marcus and Mary were educators, and so were their two daughters.  Mary M. Knight then entered politics as a candidate of the Democratic/Populist Party.  She was elected as the Mason County Superintendent of Schools. 

Mary served as Superintendent of Mason County Schools for 18 years.  During that time she worked diligently to get the five small school districts along the Western border of Mason County to consolidate.  One new larger school district could offer students far more than five smaller school districts could.  Eventually, consolidation occurred and the new school district was built in 1924.  The new school district was named Mary M. Knight School District #311 in honor of the former Superintendent of Mason County Schools who had worked so hard on their behalf.

Mary M. Knight died in Seattle, Washington on January 31, 1940 at the age of 86.