Mary Gertrude Fendall was born in 1889 in Baltimore City, and graduated from Bryn Mawr College in 1912 with a Bachelor’s degree in Mathematics and Physics.

Fendall traveled to France where she was active in the suffrage movement but returned to work for the National Woman’s Party (NWP). She was re-elected for a second term as treasurer in December 1917 after showing $117,000 in contributions to the NWP in 11 months. She was a secretary to suffragist benefactor Alva Belmont and an NWP picket line organizer who was able to help enlist nearly a thousand picketers in a March 1917 protest. Her prominent Baltimore family strongly disapproved of her work.