In 1962 together with, among others, Jomo Kenyatta and Ronald Ngala, he was part of the Kenyan delegation to the second Lancaster House Conference that negotiated for Kenya's independence from British colonial rule.
In 1967, Keen was detained and later put behind bars by the Kenyatta administration after he accused him, Tanzania's Julius Nyerere, and Uganda's Milton Obote as being the main obstacles towards the formation of the East African Community.
When section 2A of the Kenyan constitution was repealed allowing the country to be a multi-party state once again, Keen quit KANU and formed the Democratic Party of Kenya together with Mwai Kibaki.
[6] In 2016, high court judge Mumbi Ngugi dismissed a case in which Ruby Karimi had sued Keen and the Registrar of Births and Deaths to change her name and recognize the former as her father.
He was buried in his home in Namanga [8] Hornsby, Charles (1998) Multi-party Politics in Kenya: The Kenyatta & Moi States & the Triumph of the System in the 1992 Election New York: James Currey Publishers