By the late 1890s, Dr. Annie enjoyed an ever expanding medical practice, she had privileges at both St. In addition she was on the Board of the Associated Charities, The Co-operative Nurses Association, the Florence Crittenton Home for Unwed Mothers, She also served as one of the Managers to the YWCA and was the attending physician at both institutions. Dr. Annie also served as the physician for the students at  Presbyterian College, a local woman’s school, which later became Queens College. Dr. Annie’s house calls took her to various locations in the county and she treated patients from all walks of life and of any race. n addition to seeing children in her private practice, Annie Alexander lent her skills to the care of abandoned girls, to the public schools, and to the national effort of World War I. At times her zeal for the public health threatened to endanger [2] her own.   

As previously stated, "Dr. Annie" served on the board of the Crittenton home in Charlotte and attended many of the young, unwed mothers, who delivered their babies there. The Florence Crittenton Mission was launched by Charles Nelson Crittenton of New York, a businessman who turned philanthropist upon the death of his daughter.   A Crittenton home for unwed girls and their babies opened in Charlotte in 1905. Dr. Annie Alexander was named as one of a team of eleven "lady managers" entrusted with running it.  (1) [3]  She remained an official physician to the Crittenton home until her death in 1929. (2 [4]) [4]  In 1919 she adopted a boy from the Crittenton home and named him Robert Alexander.  

In December of 1917, Major B. W. Brown, of the United States Public Health Service, appointed Dr. Annie as Assistant Surgeon to oversee the medical work in Charlotte Schools. Earlier that year, she quickly diagnosed an outbreak of trachoma, a serious eye disease, in one of the city schools. (3) [5]  Dr. Annie and two nurses made regular visits to each of the schools to examine the students and prescribed treatment when necessary. She performed all of these duties while attending her regular practice. Over the course of her career, she examined thousands of school children. Dr. Annie treated diseases caused by nutritional deficiency and parasites spread in unsanitary living conditions. She also looked for any early signs of contagious diseases, especially whooping cough, measles, scarlet fever and tuberculosis.

Dr. Annie also attended soldiers at Camp Greene. Numerous communicable diseases incapacitated the men for weeks at a time. She was appointed acting assistant surgeon at Camp Greene. Because of her diminuitive stature, it was necessary for Dr. Annie to perform her surgeries standing on a small wooden stool which remains in the family. (4)