In 1887, he managed to buy the ruined chapel, and subsequently spent much of his life on Capri building the Villa San Michele.

He associated with a number of celebrities of his times, including Jean-Martin Charcot, Louis Pasteur, Henry James, and Guy de Maupassant, all of whom figure in the book.

At no point does Munthe seem to take himself particularly seriously, but some of the things he discusses are very serious, such as his descriptions of rabies research in Paris, including euthanasia of human patients, and a suicide attempt by a man convinced he had been exposed to the disease.

His work with a French ambulance corps during the First World War is mentioned only briefly, in connection with the use of hypnotic anaesthesia when no chemical anaesthetics were available – fatally injured soldiers often died with "a smile on their lips, with my hand on their forehead."

Munthe published a few other reminiscences and essays during the course of his life, and some of them were incorporated into The Story of San Michele, which vastly overshadows all his other writing both in length and popularity.

Worldwide, the book was immensely successful; by 1930, there had been twelve editions of the English version alone, and Munthe added a second preface.