He was named Prime Minister of Angola in September 2008 and remained in office until the new constitution replaced this function in February 2010.

[1] From 1978 to 1979, Kassoma was Deputy Minister of Defense for Weapons and Technology in the government of the People's Movement for the Liberation of Angola (MPLA).

[6] On 11 February 2002, Kassoma offered white farmers in Zimbabwe who lost their farms as a result of that country's land reform the opportunity to resettle on 10,000 hectares of abandoned farmland in Huambo[7][8] (specifically, in Chipipa[8]) and grow maize.

[13] Under the terms of a new constitution passed by the National Assembly on 21 January 2010, the office of Prime Minister was eliminated.

[14] Kassoma was then designated as President of the National Assembly, replacing Fernando da Piedade Dias dos Santos, who was appointed Vice-President of Angola.