Early life
J. M. Kariuki was born in Kabati-ini town in Rift Valley province. He was born to Kariuki Kigani and Mary Wanjiku.He was the only boy in a family of five siblings. In 1938, he brieflyenrolled in Evanson's Day School, but dropped out shortly due to lackof school fees. He then started working for the settler's farm until1946, when he won a bet in Nakuru Horse races. Using the bet's proceedshe then enrolled himself back to a string of schools and was able tofinish his primary school education in 1950. Later, he joined King's College in Uganda's Wakiso district for his secondary education.

Political life
J. M. Kariuki's political life probably started in 1946 in earnest,after listening to a Kenyatta speech denouncing the way colonialgovernment was handling the natives in a political rally. Its howeverlikely he was political earlier than that. His parents had earlier onbeen forced to leave their home area, Chinga,located in the Nyeri native reserve, back in 1928 to work in the whitehighlands. There, they became squatters on a European settler's farmand were expected, as was the case with other African squatterfamilies, to do the regular and seasonal jobs for wages. Such a lifetrauma was certainly likely to have made him political.

In late 1940s, he joined the primary school drama and role played inthe fight against colonial rule. While in Uganda for his secondaryeducation, he closely followed the struggles that local Kenyans werefacing from the European settlers. On 22 October 1952, he finished hissecondary school education and returned to Kenya. Shortly after that,Kenya was placed under state of emergency by the new Governor, SirEvelyn Baring, and Kariuki joined the Mau Mau uprising. After Kariuki took his oath, he started working as Mau Mau liaison officer between Eldoret and Kisumu.He also helped in soliciting money, boots and housing for Mau Mau. Thisled to his arrest in his hotel, which was working as a front to hispolitical work. He was then detained in various camps (including Kowopand Langata) from 1953 until his release, seven years later in 1960.

After his release, he managed to secure Kenyatta's approval in starting Nyeri's Kenya African National Union(KANU) branch by visiting him in detention. When Kenya becameindependent, Kariuki worked as Kenyatta's private secretary between1963 to 1969. In late 1960, Kariuki relationship with Kenyatta becameincreasingly strained as Kariuki became increasingly vocal ofKenyatta's policy. Some of their disagreement were:

Government corruption.The widening gap between rich and poor due to drought and the oil shock of 1973.Deteriorating relations among East African Community members.Unfair distribution of land: After independence, United Kingdomgovernment gave Kenyatta government funds to buy back land from thewhite settlers and redistribute it back to the natives. However, theland was never redistributed, but most of it was handed over toKenyatta's close friends. This was somehow similar to what happened inUSSR early 90s.

In 1974, he was elected as Nyandarwa's Member of parliament andbecame an assistant minister in the Kenyatta government between 1974and 1975. This was despite Kenyatta government pulling all strings atits disposal to avoid his re-election as his popularity threatened toovershadow the government of the day. He was last seen alive at theHilton Hotel, accompanied by Kenyatta's bodyguard on March 2, 1975.Several days later, Kariuki's remains were found by a Maasai herdsman,Musaita ole Tunda, in a thicket in the Ngong Hills. His fingers had been chopped off and eyes gouged out.

At the time of his death Kariuki was a millionaire. It is not clearhow he amassed his fortune so quickly without somehow engaging on thesame vice he was very critical of. His family did not benefit from hiswealth, as Kenyatta's government conspired against them. Kariuki isremembered by Kenyans as a hero as he came to represent the forceagainst the evils that have hemmed the country to this day.

Book
Kariuki wrote "Mau Mau Detainee", an account of his experience in camps during the uprising that lead to Kenya's independence.

Quotes
"Kenya has become a nation of 10 millionaires and 10 million beggars.""Every Kenyan man, woman and child is entitled to a decent and justliving. That is a birthright. It is not a privilege. He is entitled asfar as is humanly possible to equal educational, job and healthopportunities irrespective of his parentage, race or creed or his areaof origin in this land. If that is so, deliberate efforts should bemade to eliminate all obstacles that today stand in the way of thisjust goal. That is the primary task of the machinery called Government:our Government.""We fought for independence with sweat, blood and our lives. Manyof us suffered for inordinate days – directly and indirectly. Many ofus are orphans, widows and children as a result of the struggle. Wemust ask: What did we suffer for, and were we justified in thatsuffering?"

Death Investigation
A Parliamentary Select Committee was immediately established toinvestigate the circumstances surrounding Kariuki's murder. TheCommittee's report implicated a senior police officer, Joginder Singh Sokhi,senior administrative officers and politicians, but no one was everpunished. It is most likely that the committee was the means used byKenyatta's government to mitigate a potential revolt. When the reportwas finally released, the anger had subsided and likelihood of revoltmuch lower.