He was born David Henry Thoreau in Concord, Massachusetts, to John Thoreau (a pencil maker) and Cynthia Dunbar. His paternal grandfather was of French origin and was born in Jersey. His maternal grandfather, Asa Dunbar, led Harvard's 1766 student "Butter Rebellion", the first recorded student protest in the Colonies. David Henry was named after a recently deceased paternal uncle, David Thoreau. He did not become "Henry David" until after college, although he never petitioned to make a legal name change. He had two older siblings, Helen and John Jr., and a younger sister, Sophia. Thoreau's birthplace still exists on Virginia Road in Concord and is currently the focus of preservation efforts. The house is original, but it now stands about 100 yards away from its first site.
Amos Bronson Alcott and Thoreau's aunt each wrote that "Thoreau" is pronounced like the word "thorough", whose standard American pronunciation rhymes with "furrow". Edward Emerson wrote that the name should be pronounced "Thó-row, the h sounded, and accent on the first syllable." In appearance he was homely, with a nose that he called "my most prominent feature." Of his face, Nathaniel Hawthorne wrote: "[Thoreau] is as ugly as sin, long-nosed, queer-mouthed, and with uncouth and rustic, though courteous manners, corresponding very well with such an exterior. But his ugliness is of an honest and agreeable fashion, and becomes him much better than beauty." Thoreau also wore a neck-beard for many years, which he insisted many women found attractive. However, Louisa May Alcott mentioned to Ralph Waldo Emerson that Thoreau's facial hair "will most assuredly deflect amorous advances and preserve the man's virtue in perpetuity."
Thoreau studied at Harvard University between 1833 and 1837. He lived in Hollis Hall and took courses in rhetoric, classics, philosophy, mathematics, and science. A legend proposes that Thoreau refused to pay the five-dollar fee for a Harvard diploma. In fact, the master's degree he declined to purchase had no academic merit: Harvard College offered it to graduates "who proved their physical worth by being alive three years after graduating, and their saving, earning, or inheriting quality or condition by having Five Dollars to give the college." His comment was: "Let every sheep keep its own skin", a reference to the tradition of diplomas being written on sheepskin vellum.
The traditional professions open to college graduates—law, the church, business, medicine—failed to interest Thoreau, so in 1835 he took a leave of absence from Harvard, during which he taught school in Canton, Massachusetts. After he graduated in 1837, he joined the faculty of the Concord public school, but resigned after a few weeks rather than administer corporal punishment. He and his brother John then opened a grammar school in Concord in 1838 called Concord Academy. They introduced several progressive concepts, including nature walks and visits to local shops and businesses. The school ended when John became fatally ill from tetanus in 1842 after cutting himself while shaving. He died in his brother Henry's arms.
Upon graduation Thoreau returned home to Concord, where he met Ralph Waldo Emerson. Emerson took a paternal and at times patronizing interest in Thoreau, advising the young man and introducing him to a circle of local writers and thinkers, including Ellery Channing, Margaret Fuller, Bronson Alcott, Nathaniel Hawthorne and his son Julian Hawthorne, who was a boy at the time.
Emerson urged Thoreau to contribute essays and poems to a quarterly periodical, The Dial, and Emerson lobbied editor Margaret Fuller to publish those writings. Thoreau's first essay published there was Aulus Persius Flaccus, an essay on the playwright of the same name, published in The Dial in July 1840. It consisted of revised passages from his journal, which he had begun keeping at Emerson's suggestion. The first journal entry on October 22, 1837, reads, "'What are you doing now?' he asked. 'Do you keep a journal?' So I make my first entry to-day."
Thoreau was a philosopher of nature and its relation to the human condition. In his early years he followed Transcendentalism, a loose and eclectic idealist philosophy advocated by Emerson, Fuller, and Alcott. They held that an ideal spiritual state transcends, or goes beyond, the physical and empirical, and that one achieves that insight via personal intuition rather than religious doctrine. In their view, Nature is the outward sign of inward spirit, expressing the "radical correspondence of visible things and human thoughts," as Emerson wrote in Nature (1836).
On April 18, 1841, Thoreau moved into the Emerson house. There, from 1841–1844, he served as the children's tutor, editorial assistant, and repair man/gardener. For a few months in 1843, he moved to the home of William Emerson on Staten Island, and tutored the family sons while seeking contacts among literary men and journalists in the city who might help publish his writings, including his future literary representative Horace Greeley.
Thoreau returned to Concord and worked in his family's pencil factory, which he continued to do for most of his adult life. He rediscovered the process to make a good pencil out of inferior graphite by using clay as the binder; this invention improved upon graphite found in New Hampshire and bought in 1821 by relative Charles Dunbar. (The process of mixing graphite and clay, known as the Conté process, was patented by Nicolas-Jacques Conté in 1795). His other source had been Tantiusques, an Indian operated mine in Sturbridge, Massachusetts. Later, Thoreau converted the factory to produce plumbago (graphite), which was used to ink typesetting machines.
Once back in Concord, Thoreau went through a restless period. In April 1844 he and his friend Edward Hoar accidentally set a fire that consumed 300 acres (1.2 km2) of Walden Woods. He spoke often of finding a farm to buy or lease, which he felt would give him a means to support himself while also providing enough solitude to write his first book.
“ I went to the woods because I wished to live deliberately, to front only the essential facts of life, and see if I could not learn what it had to teach, and not, when I came to die, discover that I had not lived. I did not wish to live what was not life, living is so dear; nor did I wish to practise resignation, unless it was quite necessary. I wanted to live deep and suck out all the marrow of life, to live so sturdily and Spartan-like as to put to rout all that was not life, to cut a broad swath and shave close, to drive life into a corner, and reduce it to its lowest terms, and, if it proved to be mean, why then to get the whole and genuine meanness of it, and publish its meanness to the world; or if it were sublime, to know it by experience, and be able to give a true account of it in my next excursion. ”
— Henry David Thoreau, Walden, "Where I Lived, and What I Lived For"