[4] After returning to Kenya from England, where he had worked as a translator for the Moroccan Embassy in London, Murumbi became a member of the Kenya African Union political party, amidst a political ferment in East Africa caused by the beginning of the withdrawal from the African continent of the British Empire.
He played a key role in securing legal counsel for the detainees arrested in the emergency crackdown, and, together with Pio Gama Pinto, raised objections to the continuance of British Imperial dominion in Kenya through Indian newspapers such as the Chronicle.
However, around this time Murumbi became uneasy with what he perceived as Kenyatta's increasing authoritarianism in dealing with political opponents, and the increasing corruption that he witnessed rapidly developing within the new Kenyan government order, and subsequently his concerns were borne out when Kenyatta began to use government power to engage in land grabbing in the late 1960s and 1970s.
As Pheroze Nowrojee stated: The assassination of Pinto illustrated to Murumbi the shocking extent to which the new government had departed from its promises.
After resigning from the office of the Vice-President in November 1966 through which was officially announced at the time to be on account of ill health, Murumbi withdrew from politics.
After leaving politics Murumbi became the acting chairman of the Kenyan National Archives, and later co-founded 'African Heritage' with Alan Donovan, which went on to become the largest Pan-African art gallery on the continent.