Mary Johnston (1930-2017) pursued a career as an elementary public school teacher and thereafter as public school principal in Waterloo, Ont. She was widely known for the contributions she made to education-related local and provincial committees as well as to the Presbyterian church and to historical groups in the Region. During her 37 year career in education she was presented with numerous awards including the Queen's jubilee medal three times, the K-W Oktoberfest Woman of the Year Award and the Wiegand Award for Teaching Excellence.

Mary Johnston was born to Joseph Samuel and Marion Halley (nee Leslie) Johnston in Edmonton but moved to Waterloo at a young age, attending elementary and secondary school in the city. She was a graduate of Stratford Teacher's College and she received her Bachelor of Arts Degree from the University of Western Ontario (1957). She also held a B.Ed. Degree (1963) and a M.Ed. Degree (1968) from the University of Toronto.

She began her teaching career at a rural one room school located on Bearinger Road, now located in the City of Waterloo. She then taught at MacGregor Public School in Waterloo. Her next position was as vice-principal of Empire, followed by Centennial Public School in Waterloo. She later served as principal of Brighton and Winston Churchill. In 1977 she was the first principal of Keatsway, then principal of Macgregor Senior Public School from which she retired in 1987. Her appointment to principal of Brighton in 1969 marked the first time there was a female principal in Waterloo history.

Mary was an active member of many local education board committees and provincial committees. She was a member of the Ontario Teachers' Federation advisory committee to circular 14, and was Regional Professional Development Chairwoman for the Midwestern region of the Ministry of Education from 1974-1976. As well, Mary was a member of local and national bodies including the Waterloo County Women Teachers' Association and the Federation of Women Teachers' Associations of Ontario. She was also involved in local community endeavours and was a member of the K-W University Women's Club. She also served on the City of Waterloo's architectural advisory committee and on the publication committee of the Waterloo Historical Society. Her interest in education and local history lead her to publish The Trail of the Slate, a history of education in the Waterloo Region.

She was ordained an elder of St. Andrew's Presbyterian Church in 1973 and had been actively involved in many of the church's activities including teaching the Communicants class and serving on the advisory committee for the student intern programme. Her work with the Presbyterian Church lead to her being awarded a life membership in the Women's Missionary Society of the Presbyterian Church in Canada.

Mary passed away on July 7, 2017.