Merton was educated in the United States and France before attending Oakham School in England. His mother died when he was six and his father when he was sixteen. After a disastrous first year at Cambridge University, during which time he fathered an illegitimate child, Merton moved to the United States to live with his grandparents. He proceeded to take his first degree and masters at Columbia University in New York City, where he made friends with a group of artists and writers who would remain his friends for life.
Merton converted to Christianity and Catholicism in his early twenties during the period he was writing his masters on William Blake. His desire to enter the Franciscans being thwarted, he taught at Bonaventure College, in Olean, New York and, following a retreat at the Trappist (Cistercian) Abbey of Gethsemani near Bardstown, Kentucky during Easter 1941, he came to a crisis with call up looming and was finally accepted as a choir novice (with the intention of becoming a priest) at Gethsemani on December 10th 1941.
During his long years at Gethsemani (where he was encouraged to write) Merton changed from the passionately inward-looking young monk of his most famous book, the autobiography The Seven Story Mountain, to a contemplative writer and poet who became well known for his dialogue with other faiths and his stand on non-violence during the race riots and Vietnam War of the 1960s, and finally achieved the solitude in a hermitage he had long desired in 1965. During these years he had many battles with his abbot about not being allowed out of the monastery, balanced by his international reputation and huge correspondence with many well-known figures of the day.
A new abbot allowed him the freedom to undertake a tour of Asia at the end of 1968, during which he memorably met the Dalai Lama in India. He died in Bangkok on 10th December 1968 (from touching a badly-grounded electric fan while stepping out of his bath), shortly after a visit to Polanaruwa in what was then Ceylon, where he had a religious experience when viewing enormous statues of the Buddha, and his body was flown back to Gethsemani where he is buried. Since his death his influence has continued to grow and he is considered by many to be a twentieth century American mystic.
Merton put a ban on publishing much of his work until 25 years after his death.