He was ambassador to Moscow in 1965, before returning to Zambia for two years, handling negotiations with Rhodesia as the president's permanent secretary.
During his tenure as foreign affairs minister for the Kenneth Kaunda regime, he played a key role in Zambian relations with the United States.
Partly because of his diplomatic efforts, Kaunda was invited to the White House for important talks with Gerald Ford in April 1975.
[3] Mwaanga was a founding member of the Movement for Multi-Party Democracy, and after the party's victory in the 1991 elections served as Minister of Foreign Affairs from 1991 to 1994.
After the 2006 elections he was reinstated as Minister of Information until his resignation in April 2007 over video footage showing him supporting breach-of-contract claims being made by a Congolese governor against the Zambian government.