Ngũgĩ wa Thiong’o, who has died aged 87, was long regarded as east Africa’s most eminent writer and, along with Chinua Achebe and Wole Soyinka, a founding father of African literature in English.

Like Achebe, his novels showed the social, psychological and economic impact of the colonial encounter in Africa, as well as the disillusion that followed independence. In later years Ngũgĩ championed writing in African languages and published fiction, drama and poetry in Gikuyu, his mother tongue.

His first novel, Weep Not Child (1964), told the story of brothers who respond in different ways to the struggle in the 1950s for independence from British rule by the Land and Freedom Army (also known as the Mau Mau) in his native Kenya, and depicted the brutality of the British in their attempts to quell the rebellion.

After Ngũgĩ showed the manuscript to Achebe at an African writers’ conference in Makere, Uganda, in 1962, Achebe secured its publication (under the name James Ngũgĩ) in the Heinemann African Writers series. It was awarded Unesco’s first prize at the World Festival of Black Arts in Senegal in 1966.

Thereafter, many more of Ngũgĩ’s novels and short stories were published in that series. A Grain of Wheat (1967), considered by some critics his best work of fiction, is set during celebrations for Kenya’s independence day and deals with issues of single-minded heroism and betrayal, as well as the sufferings of detainees and women during the struggle for freedom.

An earlier novel, The River Between (1965), featured an unhappy romance and divisions between Christians and non-Christians. It was written while Ngũgĩ was studying for a master’s degree in the UK, at the University of Leeds.

Ngũgĩ also wrote plays, including The Black Hermit (1962), which dramatises a conflict between the desire to stay with the traditional world of a rural village and the wish to benefit from modern improvements and wealth, and The Trial of Dedan Kimathi, written in 1976 with Micere Githae Mugo, focusing on the deeds and aims of a leader of the Mau Mau.

Appointed professor of English literature and fellow of creative writing at the University of Nairobi in 1967, Ngũgĩ argued successfully for the re-formation of the department to place African literatures, including oral literatures and writing in African languages, at its centre. At this time he changed his name from James Thiong’o Ngũgĩ to Ngũgĩ wa Thiong’o. He also published a series of influential essays gathered later in Homecoming: Essays on African and Caribbean Literature, Culture, and Politics (1972).

Increasingly alienated by the corruption and authoritarian policies that characterised Kenya’s government under Jomo Kenyatta and his successor, Daniel Arap Moi, Ngũgĩ was influenced in his later writing by Frantz Fanon and Marxist ideology. Petals of Blood (1977), the last of his novels composed in English, was completed while he stayed in Yalta in Crimea, as a guest of the Soviet Union. Its central character, Wanja, a barmaid and prostitute, becomes a symbol of Kenya and the capitalist exploitation of labour, raped and damaged by corrupt businessmen and politicians.

In the same year that Petals of Blood was published, Ngũgĩ became involved in creating community theatre along the lines advocated by Fanon. Together with the Kenyan playwright Ngũgĩ wa Mirii he composed a play in Gikuyu, Ngaahika Ndeenda (I Will Marry When I Want), which included members of village audiences as actors and vocal responders.

Its success, allied to its outspoken criticism of the Kenyan establishment, led to Ngũgĩ’s arrest in 1977. He was detained in Kamiti maximum security prison in Nairobi for almost a year, until released partly through the intervention of Amnesty International. Finding that he had been stripped of his professorship and facing threats to his family, he left Kenya for Britain in 1982.

While in prison Ngũgĩ had used sheets of toilet paper to write Caitaani Mutharaba-ini (The Devil on the Cross), his first novel in Gikuyu. Drawing on styles and forms reminiscent of traditional ballad singers, the novel mingles fantasy and realism to satirise wealthy Kenyans who exploit the poor.

In Britain between 1982 and 1985 he worked with the Committee for the Release of Political Prisoners in Kenya and was writer-in-residence for the London borough of Islington. He was also in demand as a speaker at conferences promoting the reading and study of African and other Commonwealth literatures, often explaining his conviction that African and other indigenous writers should cease writing fiction in English, “the language of the oppressor”.

His arguments were later published in several collections of essays, including Barrel of a Pen (1982) and Decolonising the Mind: The Politics of Language in African Literature (1986).

Born in the village of Kamiriithu, near Limuru in Kenya, Ngũgĩ was the son of Ngũgĩ wa Ndūcū, a landowner, and his third wife, Wanjiku, in a family consisting of four wives and 28 children. After primary education in the village school he was sent as a boarder to the Alliance high school near Nairobi. There students were made to speak in English only, and beaten if caught speaking Gikuyu or other indigenous languages.

On his return home after his first term, he found that his village had been razed by British forces opposing the Mau Mau insurrection. His family were divided in their attitudes to the Mau Mau; some members opposed it, and one became an informer to the British government, while a half-brother joined the movement, another was detained, and a third, who was deaf, was shot in the back when he failed to stop in response to a command he did not hear. His mother had been detained and also abused.

Ngũgĩ went on to complete a degree in English at Makerere University College in Uganda in 1963, and in 1964 won a scholarship to Leeds. That same year he married his first wife, Nyambura, a teacher, farmer and small trader. He taught English and African literatures at the University of Nairobi from 1967 to 1977, while also serving as a fellow in creative writing at Makerere University.

Following his release from detention in December 1978 and subsequent move to the UK, he remained an exile from Kenya. His one attempt to return, in 2004, resulted in a brutal robbery and a sexual assault on his second wife, Njeeri, an incident that Ngũgĩ strongly suspected was encouraged by people close to the government.

While teaching in the UK and the US, Ngũgĩ wrote several memoirs, including Detained: a Writer’s Prison Diary (1982, updated as Wrestling With the Devil, 2018), Dreams in a Time of War: a Childhood Memoir (2010), and Birth of a Dream Weaver: A Memoir of a Writer’s Awakening (2016). He also continued to write fiction in Gikuyu. His verse epic retelling the Gikuyu myth of origin, Kenda Mũiyũru: Rũgano rwa Gĩkũyũ na Mũmbi (2019), translated by Ngũgĩ as The Perfect Nine, was the first work written in an indigenous African language to be longlisted for the International Booker prize.

He was the recipient of numerous awards and honorary degrees across the world, and was often seen as a leading candidate for the Nobel prize for literature; so much so that in 2010 many reporters gathered outside his home on the day of its announcement. When it became clear that the award had gone to Mario Vargas Llosa, Ngũgĩ seemed much less disappointed than the reporters, whom he had to console.

Having separated from Nyambura, who did not accompany him into exile, Ngũgĩ married Njeeri, a counsellor and therapist at the University of California, in 1992; they separated in 2023. He is survived by 10 children and seven grandchildren.

• Ngũgĩ wa Thiong’o (James Thiong’o Ngũgĩ), writer and activist, born 5 January 1938; died 28 May 2025