Ken was born in Bori, in the Niger Delta. He spent childhood in a polygamous household of Anglican faith and eventually proved himself an excellent student, netting him a scholarship to study English at Government College Umuahia. He would complete his studies at the University of Ibadan and briefly became a teaching assistant at the University of Lagos.
However, he soon took up a government post as the Civilian Administrator for the port city of Bonny in the Niger Delta and was a strong supporter of the federal cause against the Biafrans during the Nigerian Civil War. His best known novel, Sozaboy: A Novel in Rotten English, tells the story of a naive village boy recruited to the army during the Nigerian Civil War of 1967 to 1970 and intimates the corruption and patronage in Nigeria's military regime of the time. His war diaries, On a Darkling Plain, document Saro-Wiwa's experience during the war. Additionally, Saro-Wiwa was also a successful businessman and television producer. His satirical television series, Basi & Co., is purported to have been the most watched soap opera in Africa.
In the early 1970s Saro-Wiwa served as the Regional Commissioner for Education in the Rivers State Cabinet, but was dismissed in 1973 because of his support for Ogoni autonomy. In the late 1970s, he established a number of successful business ventures in retail and real-estate, and during the 1980s concentrated primarily on his writing, journalism and television production. His intellectual production was interrupted in 1987 when he once again entered the political scene, this time as an appointee of newly-installed dictator Ibrahim Babangida, who enlisted Ken to aid the country's transition to democracy. However, Ken resigned shortly thereafter because he felt Babangida's supposed plans for a return to democracy were disingenuous. Ken's sentiments were proven correct in the coming years as Babangida failed to relinquish power. In 1993 he annulled Nigeria's general elections which would transfer power to a civilian government, sparking mass civil unrest and eventually forcing him to step-down, at least officially, in the same year.
In 1990 Saro-Wiwa began devoting most of his time to human rights and environmental causes, particularly in Ogoniland. He was one of the earliest members of the Movement for the Survival of the Ogoni People (MOSOP), which advocated for the rights of the Ogoni people. The Ogoni Bill of Rights, written by MOSOP, set out the movement's demands, including increased autonomy for the Ogoni people, a fair share of the proceeds of oil extraction, and remediation of environmental damage to Ogoni lands. In 1992, Saro-Wiwa was imprisoned for several months, without trial, by the Nigerian military government.
In January 1993 MOSOP organized peaceful marches of around 300,000 Ogoni people – more than half of the Ogoni population – through four Ogoni centers, drawing international attention to his people's plight. The same year, Shell ceased operations in the Ogoni region, while the Nigerian government occupied the region militarily.
Saro-Wiwa was arrested again and detained by Nigerian authorities in June 1993, but was released after a month. In May 1994, he was arrested and accused of incitement to murder following the deaths of four Ogoni elders. Saro-Wiwa denied the charges, but was imprisoned for over a year before being found guilty and sentenced to death by a specially convened tribunal, during which nearly all of the defendants' lawyers resigned in protest to the trial's cynical rigging by the Abacha regime. The resignation of the legal teams left the defendants to their own means against the tribunal, which continued to bring witnesses to testify against Saro-Wiwa and his peers, only for many of these supposed witnesses to later admit they had been bribed by the Nigerian government to support the criminal allegations. The trial was widely criticised by human rights organisations and half a year later, Ken Saro-Wiwa received the Right Livelihood Award for his courage as well as the Goldman Environmental Prize
Very few observers were surprised when the tribunal declared a "guilty" verdict, but most were shocked that the penalty would be death by hanging for all nine defendants. However, many were skeptical that the executions would actually occur, as the Nigerian government would face international outrage and possible sanctions and other legal action should the penalties be carried out.
But on 10 November 1995, Saro-Wiwa and eight other MOSOP leaders (the "Ogoni Nine") were executed by hanging at the hands of military personnel. According to most accounts, Ken was the last person to be hanged and thus forced to watch the death of his colleagues. Information on the circumstances of Saro-Wiwa's own death are unclear, but it is generally agreed that multiple attempts were required before the hanging finally brought Saro-Wiwa to his end. Ken's death provoked international outrage and the immediate suspension of Nigeria from the Commonwealth of Nations, which was meeting in New Zealand at the time. The United States and other countries considered imposing economic sanctions on Nigeria because of such actions.
A memorial to Saro-Wiwa was unveiled in London on 10 November 2006. It consists of a sculpture in the form of a bus, and was created by Sokari Douglas Camp, also from Nigeria. It had toured the UK the following year.