Merwin was born in New York City in 1927 and grew up in New Jersey and Scranton, Pennsylvania. He first picked up a pencil to write poetry when he was five years old, writing and illustrating hymns for his father, a Presbyterian minister. Merwin remembers being greatly transported by his father's reading of psalms and Bible passages from the pulpit: "I was fascinated by the language...I still know many of the psalms by heart." His mother also read him poetry and he considers his childhood an extremely rich and lucky one: "Those children who've grown up hearing a parent reading poems to them are changed by that forever. They have it forever."
Merwin won a scholarship to Princeton University and as a young man received some advice from Ezra Pound, urging him to learn a language and translate: "That way" he told him, "you can practice and you can find out what you can do with your language.... translation is a way of learning your own language." So after graduating in 1948, he spent another year at Princeton studying Romance languages, and upon further advice from Pound, to: "read the seeds, not the twigs of poetry," he moved to France and studied the Troubadours to learn about poetry from its source, in a language older than French. Merwin’s memoir The Mays of Ventadorn reflects upon his years in France. He went on to become a prolific translator of Latin, Spanish and French poetry, and in 1968 was awarded the PEN Translation Prize for his work in translation from 1948-1968.
In 1950 he was employed as a tutor to Robert Graves' son at their home in Majorca, and the influence of Graves is discernible in Merwin's early poetry. In 1952, his first collection, A Mask for Janus, was selected by WH Auden for the Yale Series of Younger Poets Prize. Auden praised its ornate use of form and technical virtuosity and in the book's preface he notes that Merwin has captured: "the feeling which most of us share of being witnesses to the collapse of a civilization … and in addition the feeling that this collapse is not final but that … there will be some kind of rebirth, though we cannot imagine its nature." His next two collections: The Dancing Bears (1954) and Green with Beasts (1956) are, as A Mask for Janus, characterized by traditional forms, symbolic imagery, mythical and legendary motifs, anachronistic language and themes of rebirth.
In 1956, Merwin was offered a fellowship from the Poets' Theatre in Cambridge, Massachusetts and returned to the U.S. His work underwent a shift in tone and form during the 1960s - a breaking away strict from form and an eschewing of punctuation - in reaction to the US involvement in Vietnam and the seeming nearness of apocalypse. Of his groundbreaking 1967 collection The Lice, he has said in interview "Most of [it] was written at a time when...I thought the future was so bleak that there was no point in writing anything at all. And so the poems kind of pushed their way upon me when I wasn't thinking of writing."
In 1971 Merwin won the Pulitzer Prize for poetry with The Carrier of Ladders, which continues work begun in The Lice. He donated the prize money to the draft resistance movement, writing an essay for the New York Review of Books that outlined his objections to the Vietnam War. With both of these books, he had started to take on a broader emotional range with poems that allay the bleakness of the human condition with the comfort of elegy and prayer, thus harking back to the mode of poetic address that first held his attention as a child.
In 1976 another profound shift appeared in his work when he moved to Hawaii to study Zen Buddhism. He settled in Maui, in a house he helped design and build, surrounded by acres of tropical forest, which he painstakingly restored from ruination after years of erosion and farming. The Compass Flower (1977), Opening the Hand (1983), and The Rain in the Trees (1988) "are concerned not only with what to renounce in the metropolis but also what to preserve in the country," observed Ed Hirsch in the New York Times.
A life of stillness and meditation has led Merwin's work to become increasingly more philosophical. Talking about his 2009 Pulitzer winning collection The Shadow of Sirius, he says: "The Shadow of Sirius is pure metaphor, pure imagination. But we live in it all the time. ...We are the shadow of Sirius. There is the other side of - as we talk to each other, we see the light, and we see these faces, but we know that behind that, there's the other side, which we never know. And that - it's the dark, the unknown side that guides us, and that is part of our lives all the time. It's the mystery. That's always with us, too. And it gives the depth and dimension to the rest of it." The book's three sections deal with childhood and memory, death and wisdom, and are some of the most autobiographical of his career. The Pulitzer Prize committee praised the book for its "luminous, often-tender poems that focus on the profound power of memory."
Critic Jane Frazier discusses the narrators of Merwin's poems, noting that they are often "disembodied," which allows the poems to tell themselves without the sensation of the poet leaning over their shoulders. Perhaps augmenting this disembodiment is the absence of punctuation, a feature of his work since the 1960s: "Punctuation nails the poem down on the page," he writes. "When you don't use it the poem becomes more a thing in itself, at once more transparent and more actual." For similar reasons he only uses recycled paper for his writing, which he does always by hand: "I can't imagine ever writing anything of any kind on a machine. I never tried to write either poetry or prose on a typewriter. I like to do it on useless paper, scrap paper, because it's of no importance. If I put a nice new sheet of white paper down in front of myself and took up a new, nicely sharpened anything, it would be instant inhibition, I think. So now what?"
Echoes of the pulpit can be heard in WS Merwin's incantatory reading style and his voice finds natural pauses for breath in the poems. The absence of punctuation on the page means both that the final edit is in the performance, and conversely that there is no final edit, because the performance might be different each time, and with each recording.