In 1942, following his parents' divorce, Snyder moved to Portland, Oregon with his mother and his younger sister, Anthea. Their mother, Lois Snyder Hennessy (born Wilkey), worked during this period as a reporter for The Oregonian. One of Gary's boyhood jobs was as a newspaper copy boy, also at the Oregonian. Also, during his teen years, he attended Lincoln High School, worked as a camp counselor, and went mountain climbing with the Mazamas youth group. Climbing remained an interest of his, especially during his twenties and thirties. In 1947, he started attending Reed College on a scholarship. Here he met, and for a time, roomed with the education author Carl Proujan; and became acquainted with Philip Whalen and Lew Welch. During his time at Reed, Snyder published his first poems in a student journal. In 1948, he spent the summer working as a seaman. To get this job, he joined the now defunct Marine Cooks and Stewards union, and would later work as a seaman in the mid-1950s to gain experience of other cultures in port cities. Snyder married Alison Gass in 1950; however, they separated after seven months, and divorced in 1952.

Snyder was married to Uehara for twenty-two years; the couple divorced in 1989. Snyder married Carole Lynn Koda (October 3, 1947 – June 29, 2006), who would write Homegrown: Thirteen brothers and sisters, a century in America, in 1991, and remained married to her until her death of cancer. She had been born in the third generation of a successful Japanese-American farming family, noted for its excellent rice. She shared Buddhism, extensive travels, and work with Snyder, and performed independent work as a naturalist.

In the 1950s, Snyder took part in the rise of a strand of Buddhist anarchism emerging from the Beat movement. Snyder was the inspiration for the character Japhy Ryder in Jack Kerouac's novel The Dharma Bums (1958). Snyder had spent considerable time in Japan studying Zen Buddhism, and in 1961 published an essay, "Buddhist Anarchism", where he described the connection he saw between these two traditions, originating in different parts of the world: "The mercy of the West has been social revolution; the mercy of the East has been individual insight into the basic self/void." He advocated "using such means as civil disobedience, outspoken criticism, protest, pacifism, voluntary poverty and even gentle violence" and defended "the right of individuals to smoke ganja, eat peyote, be polygymous, polyandrous or homosexual" which he saw as being banned by "the Judaeo-Capitalist-Christian-Marxist West".

While attending Reed, Snyder did folklore research on the Warm Springs Indian Reservation in central Oregon. He graduated with a dual degree in anthropology and literature in 1951. Snyder's senior thesis, entitled The Dimensions of a Myth, employed perspectives from anthropology, folklore, psychology, and literature to examine a myth of the Pacific Northwest's Haida people. He spent the following few summers working as a timber scaler at Warm Springs, developing relationships with its people that were less rooted in academia. This experience formed the basis for some of his earliest published poems (including "A Berry Feast"), later collected in the book The Back Country. He also encountered the basic ideas of Buddhism and, through its arts, some of the Far East's traditional attitudes toward nature. He went to Indiana University with a graduate fellowship to study anthropology. (Snyder also began practicing self-taught Zen meditation.) He left after a single semester to return to San Francisco and to 'sink or swim as a poet'. Snyder worked for two summers in the North Cascades in Washington as a fire lookout, on Crater Mountain in 1952 and Sourdough Mountain in 1953 (both locations on the upper Skagit River). His attempts to get another lookout stint in 1954 (at the peak of McCarthyism), however, failed. He had been barred from working for the government, due to his association with the Marine Cooks and Stewards. Instead, he went back to Warm Springs to work in logging as a chokersetter (fastening cables to logs). This experience contributed to his Myths and Texts and the essay Ancient Forests of the Far West.

Back in San Francisco, Snyder lived with Whalen, who shared his growing interest in Zen. Snyder's reading of the writings of D.T. Suzuki had in fact been a factor in his decision not to continue as a graduate-student in anthropology, and in 1953 he enrolled at the University of California, Berkeley to study Asian culture and languages. He studied ink and wash painting under Chiura Obata and Tang Dynasty poetry under Ch'en Shih-hsiang. Snyder continued to spend summers working in the forests, including one summer as a trail-builder in Yosemite. He spent some months in 1955 and 1956 living in a cabin (which he dubbed "Marin-an") outside Mill Valley, California with Jack Kerouac. It was also at this time that Snyder was an occasional student at the American Academy of Asian Studies, where Saburō Hasegawa and Alan Watts, among others, were teaching. Hasegawa introduced Snyder to the treatment of landscape painting as a meditative practice. This inspired Snyder to attempt something equivalent in poetry, and with Hasegawa's encouragement, he began work on Mountains and Rivers without End, which would be completed and published forty years later. During these years, Snyder was writing and collecting his own work, as well as embarking on the translation of the "Cold Mountain" poems by the 8th-century Chinese recluse Han Shan; this work appeared in chapbook-form in 1969, under the title Riprap & Cold Mountain Poems.

Independently, some of the Beats, including Philip Whalen, had become interested in Zen, but Snyder was one of the more serious scholars of the subject among them, preparing in every way he could think of for eventual study in Japan. In 1955, the First Zen Institute of America offered him a scholarship for a year of Zen training in Japan, but the State Department refused to issue him a passport, informing him that "it has been alleged you are a Communist." A subsequent District of Columbia Court of Appeals ruling forced a change in policy, and Snyder got his passport. In the end, his expenses were paid by Ruth Fuller Sasaki, for whom he was supposed to work; but initially he served as personal attendant and English tutor to Zen abbot Miura Isshu, at Rinko-in, a temple in Shokoku-ji in Kyoto, where Dwight Goddard and R. H. Blyth had preceded him. Mornings, after zazen, sutra chanting, and chores for Miura, he took Japanese classes, bringing his spoken Japanese up to a level sufficient for kōan study. He developed a friendship with Philip Yampolsky, who took him around Kyoto. In early July 1955, he took refuge and requested to become Miura's disciple, thus formally becoming a Buddhist.

During the period between 1956 and 1969, Snyder went back and forth between California and Japan, studying Zen, working on translations with Ruth Fuller Sasaki, and finally living for a while with a group of other people on the small, volcanic island of Suwanosejima. His previous study of written Chinese assisted his immersion in the Zen tradition (with its roots in Tang Dynasty China) and enabled him to take on certain professional projects while he was living in Japan. Snyder received the Zen precepts and a dharma name (Chofu, "Listen to the Wind"), and lived sometimes as a de facto monk, but never registered to become a priest and planned eventually to return to the United States to 'turn the wheel of the dharma'. During this time, he published a collection of his poems from the early to mid '50s, Myths & Texts (1960), and Six Sections from Mountains and Rivers Without End (1965). This last was the beginning of a project that he was to continue working on until the late 1990s. Much of Snyder's poetry expresses experiences, environments, and insights involved with the work he has done for a living: logger, fire-lookout, steam-freighter crew, translator, carpenter, and itinerant poet, among other things. During his years in Japan, Snyder was also initiated into Shugendo, a form of ancient Japanese animism, (see also Yamabushi). In the early 1960s he traveled for six months through India with his wife Joanne, Allen Ginsberg, and Peter Orlovsky. Snyder and Joanne Kyger separated soon after a trip to India, and divorced in 1965.

Snyder is among those Writers who have sought to dis-entrench conventional thinking about primitive peoples that has viewed them as simple-minded, ignorantly superstitious, brutish, and prone to violent emotionalism. In the 1960s Snyder developed a "neo-tribalist" view akin to the "post-modernist" theory of French Sociologist Michel Maffesoli. The "re-tribalization" of the modern, mass-society world envisioned by Marshall McLuhan, with all of the ominous, dystopian possibilities that McLuhan warned of, subsequently accepted by many modern intellectuals, is not the Future that Snyder expects or works toward. Snyder's is a positive interpretation of the tribe and of the possible Future. Todd Ensign describes Snyder's interpretation as blending ancient tribal beliefs and traditions, philosophy, physicality, and nature with politics to create his own form of Postmodern-environmentalism. Snyder rejects the perspective which portrays nature and humanity in direct opposition to one another. Instead, he chooses to write from multiple viewpoints. He purposely sets out to bring about change on the emotional, physical, and political levels by emphasizing the ecological problems faced by today's society.

In 1966, Snyder joined Allen Ginsberg, Zentatsu Richard Baker, Roshi of the San Francisco Zen Center, and Donald Walters, a.k.a. "Swami Kriyananda," to buy 100 acres (0.40 km) in the Sierra foothills, north of Nevada City, California. In 1970, this would become his home, with the Snyder family's portion being named Kitkitdizze. Snyder spent the summers of 1967 and 1968 with a group of Japanese back-to-the-land drop-outs known as "the Tribe" on Suwanosejima (a small Japanese island in the East China Sea), where they combed the beaches, gathered edible plants, and fished. On the island, on August 6, 1967, he married Masa Uehara, whom he had met in Osaka a year earlier. In 1968, they moved to California with their infant son, Kai (born April 1968). Their second son, Gen, was born a year later. In 1971, they moved to the San Juan Ridge in the foothills of the Sierra Nevada of Northern California, near the South Yuba River, where they and friends built a house that drew on rural-Japanese and Native-American architectural ideas. In 1967 his book The Back Country appeared, again mainly a collection of poems stretching back over about fifteen years. Snyder devoted a section at the end of the book to his translations of eighteen poems by Kenji Miyazawa.

The author and Editor Stewart Brand once wrote: "Gary Snyder's poetry addresses the life-planet identification with unusual simplicity of style and complexity of effect." According to Jody Norton, this simplicity and complexity derives from Snyder's use of natural imagery (geographical formations, flora, and fauna)in his poems. Such imagery can be both sensual at a personal level yet universal and generic in nature. In the 1968 poem "Beneath My Hand and Eye the Distant Hills, Your Body," the author compares the intimate experience of a lover's caress with the mountains, hills, cinder cones, and craters of the Uintah Mountains. Readers become explorers on both a very private level as well as a very public and grand level. A simplistic touch becoming a very complex interaction occurring at multiple levels. This is the effect Snyder intended. In an interview with Faas, he states, "There is a direction which is very beautiful, and that's the direction of the organism being less and less locked into itself, less and less locked into its own body structure and its relatively inadequate sense organs, towards a state where the organism can actually go out from itself and share itself with others."

Regarding Wave appeared in January 1970, a stylistic departure offering poems that were more emotional, metaphoric, and lyrical. From the late 1960s, the content of Snyder's poetry increasingly had to do with family, friends, and community. He continued to publish poetry throughout the 1970s, much of it reflecting his re-immersion in life on the American continent and his involvement in the back-to-the-land movement in the Sierra foothills. His 1974 book Turtle Island, titled after a Native American name for the North American continent, won a Pulitzer Prize. It also influenced numerous West Coast Generation X Writers, including Alex Steffen, Bruce Barcott and Mark Morford. His 1983 book Axe Handles, won an American Book Award. Snyder wrote numerous essays setting forth his views on poetry, culture, social experimentation, and the environment. Many of these were collected in Earth House Hold (1969), The Old Ways (1977), The Real Work (1980), The Practice of the Wild (1990), A Place in Space (1995), and The Gary Snyder Reader (1999). In 1979, Snyder published He Who Hunted Birds in His Father's Village: The Dimensions of a Haida Myth, based on his Reed thesis. Snyder's journals from his travel in India in the mid-1960s appeared in 1983 under the title Passage Through India. In these, his wide-ranging interests in cultures, natural history, religions, social critique, contemporary America, and hands-on aspects of rural life, as well as his ideas on literature, were given full-blown articulation.

A quotation from a 1974 interview at the University of North Dakota Writers Conference (published in The Beat Vision):

As Snyder's involvement in environmental issues and his teaching grew, he seemed to move away from poetry for much of the 1980s and early 1990s. However, in 1996 he published the complete Mountains and Rivers Without End, a mixture of the lyrical and epic modes celebrating the act of inhabitation on a specific place on the planet. This work was written over a 40-year period. It has been translated into Japanese and French. In 2004 Snyder published Danger on Peaks, his first collection of new poems in twenty years.

Snyder was awarded the Levinson Prize from the journal Poetry, the American Poetry Society Shelley Memorial Award (1986), was inducted into the American Academy of Arts and Letters (1987), and won the 1997 Bollingen Prize for Poetry and, that same year, the John Hay Award for Nature Writing. Snyder also has the distinction of being the first American to receive the Buddhism Transmission Award (for 1998) from the Japan-based Bukkyo Dendo Kyokai Foundation. For his ecological and social activism, Snyder was named as one of the 100 visionaries selected in 1995 by Utne Reader.

In 2004, receiving the Masaoka Shiki International Haiku Awards Grand Prize, Snyder highlighted traditional ballads and folk songs, Native American songs and poems, william Blake, Walt Whitman, Jeffers, Ezra Pound, Noh drama, Zen aphorisms, Federico García Lorca, and Robert Duncan as significant influences on his poetry, but added, "the influence from haiku and from the Chinese is, I think, the deepest."

Snyder's life and work was celebrated in John J. Healy's 2010 documentary The Practice of the Wild. The film, which debuted at the 53rd San Francisco International Film Festival, features wide-ranging, running conversations between Snyder and poet, Writer and longtime colleague Jim Harrison, filmed mostly on the Hearst Ranch in San Simeon, California. The film also shows archival photographs and film of Snyder's life.

Gary Sherman Snyder was born in San Francisco, California to Harold and Lois Hennessy Snyder. Snyder is of German, Scots-Irish, and English ancestry. His family, impoverished by the Great Depression, moved to King County, Washington, when he was two years old. There they tended dairy cows, kept laying hens, had a small orchard, and made cedar-wood shingles,. At the age of seven, Snyder was laid up for four months by an accident. "So my folks brought me piles of books from the Seattle Public Library," he recalled in interview, "and it was then I really learned to read and from that time on was voracious — I figure that accident changed my life. At the end of four months, I had read more than most kids do by the time they're eighteen. And I didn't stop." Also during his ten childhood years in Washington, Snyder became aware of the presence of the Coast Salish people and developed an interest in the Native American peoples in general and their traditional relationship with nature.