In May 1954 he became assistant treasurer of the Association du Personnel Indigene de la Colonie labour union.
[1] In 1960 the Congo became independent and Nkayi was elected in the Bas-Congo district on an Alliance des Bakongo ticket to the Chamber of Deputies[1] with 107 preferential votes, the smallest margin of victory among any successful candidates.
[3] He served as Minister of Finance in Patrice Lumumba's government,[1] which was officially invested by Parliament on 24 June 1960.
[4] On 27 July Nkayi held a press conference to share his concerns about the national decline in social and economic activity following independence.
[5] In August the government sent him to Geneva to negotiate with Belgian authorities over financial and monetary concerns.