Graham was born in Victoria Park, Manchester, England. When he was 17 years old he relocated to Perranporth, Cornwall. His first novel, The House with the Stained Glass Windows was published during 1934; his first Poldark novel, Ross Poldark, was published during 1945, and was succeeded by a series of eleven further titles, the last of which, Bella Poldark, was published during 2002. The series was set in Cornwall, especially in and near Perranporth, where Graham spent much of his life. The first seven Poldark novels were turned into a BBC television series first broadcast in the UK between 1975 and 1977 which gained audiences of about 14 million viewers. It was so successful that some vicars rescheduled or cancelled church services rather than try to have them clash with the transmission of the Poldark series.
Other than the Poldark novels, Graham's most successful work was Marnie (1964), a thriller filmed by Alfred Hitchcock with Tippi Hedren and Sean Connery in the leads. The novel was also adapted as a play by Sean O'Connor (producer) in 2001 and returned the story to its original British setting and bleak ending. Five of Graham's other books were filmed, including The Walking Stick, Night Without Stars and Take My Life.
Graham was an accomplished author of suspense novels and during the course of his life wrote nearly thirty novels (in addition to the twelve Poldark books). A 1941 spy thriller Night Journey set in the contemporary Nazi-occupied Europe preserves some of the opinion of the time, with the protagonist believing that Britain was perhaps going to lose the war but is determined to "go down fighting". Graham also wrote a history of The Spanish Armadas and an historical novel, The Grove of Eagles, based during that period. (The plural "Armadas" refers to a lesser-known second attempt by Philip II of Spain to conquer England during 1598, which Graham argued was better planned and organised than the famous one of 1588 but was foiled by a fierce storm scattering the Spanish ships and sinking many of them).
He married Jean Williamson during September 1939, a woman he had first met during 1926 when she was 13 years old. She died in December 1992. During his youth he was a keen tennis player, recording in his diaries how many sets he played each day. He lived in Perranporth from 1925 until 1959, briefly in the south of France during 1960 and then settled in East Sussex. He was Chairman of the Society of Authors and a Fellow of the Royal Society of Literature, and during 1983 was honoured with the Order of the British Empire.
Graham's autobiography, Memoirs of a Private Man, was published by Macmillan during 2003. To celebrate the centenary of his birth, the Royal Cornwall Museum in Truro, Cornwall, had an exhibition devoted to his life and works (Poldark's Cornwall: The life and times of Winston Graham) from mid-June to mid-September 2008, coinciding with re-publication of the Poldark novels by Pan Macmillan.
The Winston Graham Historical Prize was initiated as part of the Centenary Celebrations. Funded by a legacy from the author and supported by Pan Macmillan it is for a work of unpublished fiction, preferably with an association with Cornwall. Details can be obtained from the Royal Cornwall Museum.
The majority of Winston Graham's manuscripts and papers have been donated to the Royal Institute of Cornwall by his son Andrew Graham (academic) and daughter Rosamund Barteau. Further papers are housed at the Howard Gotlieb Archival Research Center at Boston University.