He served in the government and cabinet of Jomo Kenyatta, Kenya's first president, for six years, during which time he held the post of member of parliament for the Gem Constituency and the portfolios of Minister of Natural Resources and the Ministry of Foreign Affairs.
Though sent to study the social sciences, Argwings-Kodhek's interests lay with the law, and he lost his scholarship when he switched to that subject, forcing his family to sell their assets in order to finance his education.
Though he was offered a position in the Department of the Attorney General, he rejected the low salary — which was a third of that of his white peers — and went instead into private practice.
His status as colonial Kenya's only Black lawyer exposed him to repeated harassment by police officers, who regularly requested his documentation and occasionally inhibited his access to areas affected by the state of emergency declared by the British.
[6] Though national political parties were prohibited under the state of emergency proclaimed by the British, Argwings-Kodhek circumvented this ban in 1956 by establishing the Nairobi District African Congress.