Mary Esslemont graduated in medicine from Aberdeen University in 1923. As a student she had been the first female President of the Students' Representative Council.
She became Assistant Medical Officer of Health in Yorkshire, but in 1929 returned to Aberdeen where she was a general practitioner until her retirement in 1963. She served on Aberdeen University Council for over 40 years and was its first female Assessor.
She was a lifelong member of the BMA and was the only Scot, and only woman, to represent the Association in negotiations with government prior to the establishment of the NHS. She was active in many other local, national and international organisations. She is commemorated by a plaque at 30 Beechgrove Terrace.