Margaret Ritchie spent her early life in Bay City, Michigan and received a diploma from Skidmore School in Saratoga Springs, New York in 1916 and attended Columbia University Teachers College in New York City where she received her B.S. degree in 1918 and her M.A. in 1930.

Margaret was an assistant instructor of foods and chemistry at Columbia before joining the home economics staff at Battle Creek College in Michigan, where she taught for 18 years, eventually becoming the director of the home economics department. Ritchie came to the University of Idaho in 1938 as Head of Home Economics. She retired as department head in 1959, but continued to teach until forced to retire due to age in 1965. She then taught at California Polytechnic College in Pomona until 1968.

An active member of the University of Idaho and Moscow, Idaho communities, Margaret was a member and officer in many organizations including the Home Economics Association, Idaho Home Economics Association, American Dietetics Association, and Moscow Dieticians Group. She served on the board of Church Women United and was active in Meals on Wheels and the Moscow Chamber of Commerce. She was also a member of the American Association of University Women and the PEO Sisterhood. The University of Idaho Margaret Ritchie School of Family and Consumer Sciences is named in her honor.