Carnegie's professional achievements include: serving as dean of the school of nursing at Florida Agricultural and Mechanical University; becoming the first black nurse appointed to the board of the Florida Nurses Association; editing the American Journal of Nursing for 35 years; authoring the award-winning book The Path We Tread: Blacks in Nursing Worldwide; initiating the baccalaureate nursing program at Hampton University; serving as president of the American Academy of Nursing; and receiving eight honorary doctorates in addition to numerous professional awards. She was inducted into the American Nurses Association Hall of Fame in 2000.
Mary Carnegie would later meet a more political form of prejudice against her and other black nurses. The Florida State Nurses Association (FSNA) had finally allowed for black nurses to join their association. This may have seemed like a great achievement for black nurses, except that their only responsibility was to pay dues, which according to Carnegie was the same as “taxation without representation”. This could clearly be seen as the FSNA allowed one black nurse to join their board (the president of the Florida State Association of Colored Graduate Nurses) but did not allow them to vote.
Since Mary Carnegie was so motivated and determined to put a dent in the racial equality in the nursing field, she eventually won over the FSNA's board after becoming a member (elected president of the FSACGN). Since she was so outgoing, vocal and determined to be heard in their meetings, even though her "spot" on the board was a more be seen and not heard from position, Carnegie made sure to voice her opinions. This eventually led to the board's decision to grant her full rights and responsibilities within the FSNA in 1949.