[1][2] In 1908, Martha Minerva Franklin and Adah B. Thoms, two of Mahoney's colleagues, met in New York City to found the National Association of Colored Graduate Nurses (NACGN).

[2] An increase in the acceptance of Black women into notable medical positions, as well as the integration of the NACGN with the American Nurses Association, prompted the dissolution of the organization in 1951.

The Phillips School curriculum included teachings on values such as morality and humanity alongside general subjects like English, History, and Mathematics.

Black women in the nineteenth century faced systemic barriers to formal training and career opportunities as licensed nurses.

[7] Mahoney was admitted into a sixteen-month program at the New England Hospital for Women and Children (now the Dimock Community Health Center) in 1878 at the age of thirty-three, alongside thirty-nine other students.

[8] The criteria the hospital used in the student selection process emphasized that the forty candidates would be "well and strong, between the ages of twenty-one and thirty-one, and have a good reputation as to character and disposition".

[7] It is presumed that the administration accepted Mahoney, despite not meeting the age criteria, because of her connections to the hospital through prior work as a cook, maid, and washerwoman there when she was eighteen.

The intensive program consisted of long days with a 5:30 A.M. to 9:30 P.M. shift, which required Mahoney to attend lectures and lessons to educate herself through instruction of doctors in the ward.

Three quarters of the program consisted of the nurses working within a surgical, maternity or medical ward with six patients they were responsible caring for.

The last two months of the extensive 16-month long program required the nurses to use their newfound knowledge and skills in environments they were not accustomed to; such as hospitals or private family homes.

After completing these requirements, Mahoney graduated in 1879 as a registered nurse alongside 3 other colleagues — the first Black woman to do so in the United States.

As Mahoney's reputation quickly spread, she received private-duty nursing requests from patients in states in the north and south east coast.

[13] It is said that Frederick Douglass, a prominent African American abolitionist and formerly enslaved person of the time, was distantly related to Mahoney, which became one of the influences in her active participation against the repercussions of slavery and racial discrimination against minorities in the United States.

[11] From 1911 to 1912, Mahoney served as director of the Howard Colored Orphan Asylum for Black children in Kings Park, Long Island, New York.

Today, the Mary Mahoney Award[19] is bestowed biennially by the ANA in recognition of significant contributions in advancing equal opportunities in nursing for members of minority groups.