[2] He was selected as the running mate of Edward Lowassa, the CHADEMA presidential candidate for the 2015 election, which necessitated his defection.
In 1978, he left for England to study at the University of Reading (advanced diploma) and later joined the Zanzibar Ministry of Education as a planning officer.
[4] Following the end of one-party system in the 1990s, Duni joined the opposition Civic United Front party.
[2] He was the thrice running mate of the party's perennial candidate Ibrahim Lipumba, in the 1995, 2005 and 2010 presidential elections.
Following the 2010 election, President Ali Mohamed Shein appointed him as the Zanzibari Minister for Health,[5] and following a minor cabinet reshuffle in 2014, he was transferred to the Infrastructure and Communications docket.