[3][4] Due to their involvement with the Railroad, the Gardners met many abolitionists like Harriet Tubman, Sojourner Truth, Charles Sumner, Lewis Hayden, and John Brown.

[2] Gardner was a gifted student and won several scholarships, but because academic and professional opportunities for black women were limited, she trained as a dressmaker.

[2][5] As a young woman, Gardner became active in her church and in the anti-slavery movement while making her living as a dressmaker, and later as keeper of a boarding house.

As an activist she knew and worked with many abolitionist leaders including Frederick Douglass, William Lloyd Garrison, and Wendell Phillips.

[6] Gardner and her mother became founding contributors of the African Methodist Episcopal Zion church in Boston when it raised funds to move locations in 1865.

[7] Gardner's fundraising efforts met with resistance in 1884, when members of the male-dominated AMEZ Church objected to the creation of a women's society.