Margaret Libby Barr was born September 8, 1904 in Harriman, Tennessee. She was the daughter of Dr. Orin G. Libby and Eva Cory Libby. Dr. Libby was chair of the History Department at the University of North Dakota (UND) from 1902 to 1945. Margaret graduated from UND with a Bachelor of Science degree in Commerce in 1926 and taught in the Bemidji, Minnesota, school system.

She moved back to Grand Forks after marrying Paul E. Barr on June 8, 1932. Paul Barr was head of the art department at UND for 25 years, from 1928 to 1953. She assisted with the publication of his book, North Dakota Artists, in 1953. Paul Barr died on December 22, 1953. They had two children: Robert and Martha.

After her husband's death, Margaret was an Associate Professor of Business and Vocational Education at UND from 1954 until 1975. She added a Master of Science degree in Education from UND in 1956. In 1974, she was awarded the Charles DeBruyn Kops award for excellence in teaching and loyal service to UND. She co-authored the 1977 book University of North Dakota Pottery: the Cable Years, with her son Robert Barr and UND art professor Donald H. Miller. In 1987, she was presented with the Elwyn B. Robinson award for preservation of North Dakota history. This award was given because of her establishment of the Cable Pottery Collection at the UND's Hughes Fine Arts Center. During that same year, she was bestowed with the President's Award for outstanding service to UND.

She was also active in several Grand Forks organizations: Chapter D of the P.E.O. Sisterhood, Franklin Club, Round Table Club, Business and Professional Women, UND Faculty Wives, Alpha Phi and was an active member of St. Paul’s Episcopal Church. She was chair of the publications committee, which published Windows of St. Paul's Episcopal Church, 1880-1980.

Margaret Libby Barr died May 16, 1988, in Grand Forks.