Self-educated and thrown early upon his own resources, he began in 1814 to earn his living by working in a clock factory in Plymouth, Connecticut, and for many years after 1815 he peddled books and merchandise, chiefly in the southern states. He began teaching in Bristol, Connecticut in 1823, and subsequently conducted schools in Cheshire, Connecticut, in 1825-1827, again in Bristol in 1827-1828, in Boston, Massachusetts in 1828-1830, in Germantown, now part of Philadelphia, Pennsylvania, in 1831-1833, and in Philadelphia in 1833. As a young teacher he was most convinced by the educational philosophy of the Swiss pedagogue Johann Heinrich Pestalozzi.
In the spring of 1830 he married Abigail May, the sister of Samuel J. May, the reformer and abolitionist. Alcott himself was a Garrisonian abolitionist, and pioneered the strategy of tax resistance to slavery which Henry David Thoreau made famous in Civil Disobedience. Alcott publicly debated with Thoreau the use of force and passive resistance to slavery; along with Thoreau he was among the financial and moral supporters of John Brown and occasionally helped fugitive slaves escape on the Underground Railroad.
Alcott sometimes refused corporal punishment as a means of disciplining his students; instead, he offered his own hand for an offending student to strike, saying that any failing was the teacher's responsibility. The shame and guilt this method induced, he believed, was far superior to the fear instilled by corporal punishment; when he used physical "correction" he required that the students be unanimously in support of its application, even including the student to be punished.
As assistants in the Temple School, Alcott had two of nineteenth-century America's most talented women writers, Elizabeth Palmer Peabody (who published A Record of Mr. Alcott's School in 1835) and more briefly Margaret Fuller; as students he had the children of the Boston intellectual classes, including Josiah Quincy, grandson of the president of Harvard University. Alcott's methods were not well received; many readers found his conversations on the Gospels close to blasphemous, a few brief but frank discussions of birth and circumcision with the children were considered obscene, and many in the public found his ideas ridiculous. (For instance, the influential conservative Unitarian Andrews Norton derided the book as one-third blasphemy, one-third obscenity, and the rest nonsense.) The school was widely denounced in the press, with only a few scattered supporters, and Alcott was rejected by most public opinion. After the school closed Alcott was increasingly financially desperate as the controversy caused many parents to remove their students. In a later "parlor school," Alcott alienated many parents by admitting an African American child to the class, whom he then refused to expel in the face of protests. Alcott's pedagogy was a forerunner of progressive and democratic schooling.
In 1840 Alcott removed to Concord, Massachusetts. After a visit to England, in 1842, he started with two English associates, Charles Lane and Henry C. Wright, at "Fruitlands", in the town of Harvard, Massachusetts, a utopian socialist experiment in farm living and nature meditation as tending to develop the best powers of body and soul. The experiment quickly collapsed, and Alcott moved his family to Still River, a village within Harvard, in January 1844. In November, the family returned their Concord home "Hillside (later renamed "The Wayside" by Nathaniel Hawthorne) near that of Ralph Waldo Emerson. Alcott removed to Boston four years later, and again back to Concord after 1857, where he and his family lived in the Orchard House until 1877. While there, Alcott served as Superintendent to the Concord Public Schools in 1860-1861.
He spoke, as opportunity offered, before the "lyceums" then common in various parts of the United States, or addressed groups of hearers as they invited him. These "conversations" as he called them, were more or less informal talks on a great range of topics, spiritual, aesthetic and practical, in which he emphasized the ideas of the school of American Transcendentalists led by Emerson, who was always his supporter and discreet admirer. He often discussed Platonic philosophy, the illumination of the mind and soul by direct communion with Spirit; upon the spiritual and poetic monitions of external nature; and upon the benefit to man of a serene mood and a simple way of life. His teachings greatly influenced the growing New Thought movement of the mid 1800s.
Alcott's published books, all from late in his life, included New Connecticut, Tablets (1868), Concord Days (1872), and Sonnets and Canzonets (1882). Earlier he had written a series of Orphic Sayings which were published in The Dial as examples of Transcendentalist thought. The sayings, though called oracular, were considered sloppy or vague by contemporary commentators as well as twentieth-century ones. He left a large collection of journals and memorabilia, most of which remain unpublished. He died in Boston on March 4, 1888. Just two days later, his daughter, Louisa May Alcott, died of aftereffects of mercury poisoning.
Margaret Fuller referred to Alcott as "a philosopher of the balmy times of ancient Greece—a man whom the worldings of Boston hold in as much horror as the worldings of Athens held Socrates.
From the other perspective, Alcott's unique teaching ideas created an environment which produced two famous daughters in different fields, in a time when women were not commonly encouraged to have independent careers. His ideas also helped to found one of the first adult education centers in America, and provide the foundation for future generations of liberal education. Many of Alcott's educational principles are still used in classrooms today, including "teach by encouragement," art education, music education, acting exercises, learning through experience, risk-taking in the classroom, tolerance in schools, physical education/recess, and early childhood education.
While many of Alcott's ideas are still on the liberal/radical edge today, they are still common themes in society, including vegetarian/veganism, sustainable living, and temperance/self control.