Henry Nanton Murray Sedgwick was born on December 2, 1840, in St. Peters, Antigua, West Indies, son of Samuel Sedgwick (1798-1861), a physician in the West Indies.

He was a surgeon. He studied medicine in London, England, and in 1863, he enrolled in the Royal Navy. In the early 1870s, he served as a Fleet Surgeon on board the Royal Navy ship Salamis. In the 1890s, he served on the vessel Duke of Wellington. After he retired from the Royal Navy, he worked as a Deputy Inspector General of Hospitals in Portsmouth, England. He was a member of the Royal College of Surgeons of England.

In 1880, he married Mary Constance Aldous née Gray (1843–). He died on December 23, 1926, in Portsmouth, Hampshire, England.