The young Highmore studied at Sherborne School, thence to Oxford where he studied medicine after taking his BA and MA at Trinity College. A Batchelor of Physics in 1641, he was created Doctor of Medicine by special decree of King Charles I.

In 1642, Highmore was a student at Oxford when King Charles I from the first battle of the Civil War at Edgehill with his Royal Physician, William Harvey.The two physicians formed a life-long friendship and both worked on the circulation of blood. Highmore dedicated his most famous book, 'Corporis Humani Disquisitio Anatomica', published in 1651 and describing for the first time the cavity in the human head which bears his name, to Harvey.

Highmore became emminent for his books on other subjects such as ' The History of Generation', published in 1651. He was held in the highest esteem by contemporary scientists such as Robert Boyle, Oldenburg and William Petty.

The son of a vicar, Highmore declined to take any fees from the clergy.

Nathaniel was the elder son of the Rector at Purse Caundle in 1613/14, also named Nathaniel. He was born in Fordingbridge but brought to the rectory which still stands to the north of the church at Purse Caundle.

Highmore settled as a physician in Sherborne and the surrounding area c. 1644, until his death in 1685, aged 71. He took an active part in civic life as governer of Sherborne School (to which he left a legacy of £5 per year to send a boy to university), a brother of the Almshouse, and he served as a Justice of the Peace for Dorset.

He asked to be buried within the parish parish church at Purse Caundle and lies buried next to the altar, possibly with his wife, of the church where his father was rector.

Peter Mews, his contemporary and born in Purse Caundle, was the last of the warrior-bishops and faught in the Civil War.