James Hamilton was born in Edinburgh in 1767. He was one of two sons of Alexander Hamilton (1739-1802), Professor of Midwifery at Edinburgh University. James Hamilton was given medical training by his father and became his assistant at the age of twenty-one. He and his father founded Edinburgh's Lying-in Hospital in Park Place in 1793, and later on this enterprise would become supported partly from his own funds.

In 1800, Hamilton succeeded his father as Professor of Midwifery at the University. Their subject however had been slow to be accepted by the Senatus Academicus as part of the medical curriculum and in 1815 Hamilton raised the matter of recognition for midwifery. He faced hostility however, particularly from Dr. James Gregory (1753-1821), and recognition would not be achieved until 1830.

Although his classes were, for a long time, non-essential for graduation, they were well attended, and Hamilton's contribution to midwifery included advocacy of uterine suture after Caesarian operations and the introduction of the term 'eclampsia' for convulsions in labour or puerperium.

Hamilton's publications included A collection of engravings designed to facilitate the study of midwifery (1796), Hints for the treatment of the principal diseases of infancy and childhood (1809), and Practical observations on various subjects relating to midwifery (1836-1837).