Born as Ernest Thompson in the coastal town of South Shields, County Durham, England, on August 14, 1860, the illustrious author of Wild Animals I Have Known embraced the ancestral surname Seton in 1901. His Scottish forebears, supporters of Prince Charles during the ill-fated Stuart Rebellion of 1745, sought refuge in England, where they turned to shipbuilding and ownership. When the family patriarch, Joseph Logan Thompson, faced the ruin of his merchant fleet, they ventured across the Atlantic to Canada in 1866. Nestled for a time in the rustic charm of Lindsay, Ontario—a haven encircled by dense forests—young Seton cultivated a profound admiration for the wilderness. Though the family departed in 1870, Seton had already mastered many woodcraft skills that would later distinguish him as a preeminent expert. It was during his school days in Toronto that Seton's artistic flair emerged, leading him to sketch the birds and beasts that captivated him. He honed his craft at the Toronto School of Art from 1877 to 1879 before furthering his studies at London's esteemed Royal Academy of Painting and Sculpture in 1881.

In 1882, Seton ventured to the untamed edges of south-central Canada, joining his brother Arthur on a homestead near Carberry, Manitoba. There, amidst the wilderness, he found his muse among the wild creatures he so admired: wolves, grizzlies, moose, and buffalo. The following year, Seton traveled to the bustling heart of New York City, fervently seeking to sell his art to publishers and fellow artists. His initial successes came with Sacket, Williams & Betzig, lithographic publishers, leading to a prolific contract to create a thousand sketches for Century Publications' ambitious twelve-volume dictionary. His nature stories found homes in esteemed magazines such as St. Nicholas.

April 1884 saw Seton's return to Toronto, but soon he was back amid the rugged landscapes of Manitoba. His artistic journey led him between Carberry, New York City, Washington, D.C., and Paris, where he both studied and produced a wealth of art. Seton's work, Birds of Manitoba, was handed over to the Smithsonian Institution by the close of 1890, and in 1892, his evocative painting "The Sleeping Wolf" was honored with an exhibition at the prestigious Grand Salon of Painting in Paris. Meanwhile, his literary pursuits flourished, culminating in the 1898 publication of Wild Animals I Have Known, a collection that swiftly rose to best-seller status and is now celebrated as a classic.

In 1902, Seton pioneered the Woodcraft Indians, the inaugural organization dedicated to outdoor adventures for boys. This initiative, later known as the Woodcraft League, laid the foundation for what would evolve into the Boy Scouts of America. Seton's leadership was pivotal; he chaired the committee that inaugurated the Scouts in 1910 and served as chief scout for five formative years. His contributions were instrumental in crafting the first Boy Scout's Handbook in 1911.

Seton's personal life saw him marry Grace Gallatin in 1896, a staunch advocate for women's suffrage and a celebrated author of travel books. Their union bore a daughter, Ann, who would achieve acclaim as a best-selling author of historical romances in the 1940s and 1950s. The couple divorced in 1930, after which Seton relocated to the sunlit expanses of New Mexico. He found companionship once more with Julia Buttree, his former secretary, whom he married in 1935. Seton's journey concluded in Santa Fe, New Mexico, where he passed away on October 23, 1946.