His date and place of birth are disputed. The year is given as either 1831 or 1835; the date when given is July 31. Accounts cite either Paris or New Orleans as his likely place of birth. A contemporary obituary cites a statement made by du Chaillu referring to “the United States, my country by adoption, and . . . France, my native land.”

His father, a man of considerable means, was engaged in the West African trade and owned a trading depot on the Gabon coast, a few miles north of the Equator. He had friendly relations with most of the coastal tribes.

After Paul’s mother died when he was fifteen, he accompanied his father to Africa and lived for three or four years on the coast. There he was educated by missionaries, and acquired an interest in and knowledge of the country, its natural history, its natives, and their languages.

He was a bright, enterprising youngster, who spent most of his time talking with the natives, hearing their stories and learning their dialects and ways of thinking and living. He liked better to listen to the stories of the native traders than to learn the business of his father. . .

It was there that Du Chaillu heard many of the stories of wild animals, strange tribes and curious customs said to exist in the interior of Africa, which filled him with a tremendous curiosity about this mysterious region.

In 1853, his father took him back to the United States, but the wild tales the boy had heard had fascinated him and excited him to find out how much was true of what the seacoast natives said of the cannibals, pygmies, gorillas, and other marvels of the Great Forest. No white man had previously penetrated more than a few miles into the interior along this part of the coast.

When his father died, he was well-prepared to inherit his father’s prosperous trading business, being already familiar with the coastal tribes and languages. Instead, however, he decided to become an explorer.

The equatorial regions of Africa were at that time entirely unknown, no white man having ventured more than a few miles inland. The area was so dangerous and inhospitable for Europeans that it was known as “the white man’s grave.” Du Chaillu’s parents were both dead (and so couldn’t object); he was more or less inured to the harsh climate, was on friendly terms with the natives, fluent in their language, and had already accompanied some of them on short term hunting expeditions in the interior. He believed this gave him a unique ability to do what no white man had ever done, a systematic exploration of the interior of equatorial Africa.

So in 1856, at the age of 20, he set out for an extended exploration of Africa. By that time, he became a U.S. citizen and gained the support of the Philadelphia Academy of Natural Sciences for an expedition to explore Gabon.

He set up a base village on the shore of the Fernand Vaz River (one of the outlets of the Ogowe River). From there he traveled extensively over a region extending more than 300 miles inland from the coast, and 250 miles north and south. He studied plant and animal life, tribal customs, geography, and collected samples of dozens of unknown species. He made maps, went on hundreds of hunting expeditions, lived in native villages, learned several new inland languages, spoke with the natives about their beliefs and customs, and kept careful records of all his observations.

During his travels he observed gorillas, known to non-locals in prior centuries only from an unreliable report by Hanno the Navigator of Carthage in the 5th century BC, and known to scientists in the preceding years only by a few skeletons. He brought back dead specimens, and presented himself as the first white person to have seen them.

He was the first white man to hunt gorillas, and many other unique species of fauna, and the first to have contact with any of the inland tribes. He continued his explorations for over three years, at which point all of his supplies were completely exhausted.

On his return to New York in 1859 he wrote his first book, the story of his discoveries, titled Explorations and Adventures in Equatorial Africa. In book’s preface he states:

“I traveled — always on foot, and unaccompanied by other white men — about 8,000 miles. I shot, stuffed, and brought home over 2,000 birds, of which more than 60 are new species, and I killed upwards of 1,000 quadrupeds, of which 200 were stuffed and brought home, with more than 80 hitherto unknown to science. I suffered fifty attacks of the African fever, taking, to cure myself, more than fourteen ounces of quinine. Of famine, long-continued exposures to the heavy tropical rains, and attacks of ferocious ants and venomous flies, it is not worthwhile to speak. My two most severe and trying tasks were the transportation of my numerous specimens to the seashore and the keeping of a daily journal, both of which involved more painful care than I like even to think of.”

The book aroused controversy, because it conflicted with prevailing geographical, zoological, and ethnological theories. His book was so full of astounding adventures and strange customs that it was met by disbelief by many people, until his findings were substantially confirmed by later explorers.

In the book he told of gorilla, of which he had brought back the first specimens and which he had been the first white man to see and hunt; of the fierce cannibal tribes, the Fans, who filed their teeth to keep them sharp; of the ravages of the Baskonay ants, which marched in dense columns miles in length, and who were marshaled by officers and generals; of hunting elephants with pitfalls; of a new variety of snake, less than four feet long and six and eight inches thick, which lies in the open places in the woods and whose bite is instantaneous death, and of many other equally unique sights.

But the book was greeted with shouts of laughter and derision from one end of the American continent to the other. Mr. and Mrs. and Miss Gorilla was the common jest, and the name Du Chaillu became a byword for a fanciful storyteller. Du Chaillu was only 26 when his first book was published. He was unable to answer satisfactorily the storm of questions hurled at him; consequently nobody believed him, except the Royal Geographical Society in England, which always valiantly and vigorously defended his truthfulness.

Du Chaillu had even greater things planned however. At the end of 1863 he returned again to Africa, fully equipped for an even more ambitious expedition. This time he intended to cross the interior of equatorial Africa on foot, with a band of about a dozen native porters.

On this expedition he visited many tribes hitherto unknown. While in Ashango Land in 1865 he was elected King of the Apingi tribe.

This expedition was beset with many difficulties, and he had to return to the coast after only two years.

He returned to America, and in 1867 wrote his second book A Journey to Ashango Land. The map accompanying Ashango Land was of unique value, but the explorer’s collections were lost when he was forced to flee from the hostility of the natives.

This time he discovered the pygmies of the Dark Forest, but his descriptions of the little people were again received with incredulity.

Gradually each of Du Chaillu's discoveries was confirmed by later explorers — by Schweinfurth, Stanley, Sir Harry Johnston, and others. Many years ago they were all verified; but the name Du Chaillu none the less still remains to most Americans that of a romance. In a certain sense Du Chaillu is himself responsible for this feeling, for all his descriptions are so vivid and are so thrillingly told that the reader feels he is reading a work of pure invention, rather than a narrative of actual experience.

With this second expedition his explorations in Africa ended.

After publishing his second book he spend the next five years (1867–1871) writing a very exciting series of adventure books for young people based on his travels, complete with carefully crafted illustrations. The first two books, Stories of the Gorilla Country and Wild Life Under the Equator, recount various episodes from his years in Africa, including both of his major expeditions as well as his teenage years. His two subsequent books, Lost in the Jungle and My Apingi Kingdom, give a chronological account of his first expedition, and the fifth book, The Country of the Dwarfs, deals exclusively with his ill-fated second expedition.

After returning to the United States and writing his books, Du Chaillu never chose to settle down, but continued to travel. Now he turned his attention to northern Europe. He spent the next few decades traveling extensively in Sweden, Norway, Lapland and Finland. He coined the phrase “Land of the Midnight Sun,” which was the name of one of his major works on his northern explorations, the other being The Viking Age. He wrote only one book for children regarding his northern travels, The Land of the Long Night (1899).

His 1889 work The Viking Age is a very broad study of the prehistoric antiquities of the Scandinavian peninsula from the Bronze Age to the Middle Ages (including literary remains), and demonstrating what is now generally recognized, the important Norse and Swedish cultural dimension to the Germanic settlements of Britain during the fifth to seventh centuries. This book (in two volumes) is now very rare.

Paul Du Chaillu died on the 29th of April 1903, in St. Petersburg, following a stroke of paralysis, while on his way home from Russia.