[1] In November 2006, she was appointed to the KwaZulu-Natal Executive Council by Premier S'bu Ndebele; she succeeded Blessed Gwala of the Inkatha Freedom Party as MEC for Public Works.
[2] She held that office until the 2009 general election,[3] in which she was re-elected to her legislative seat, ranked sixth on the ANC's provincial party list.
She left that office on 8 October 2013, when she was elected as Speaker in the legislature, succeeding Peggy Nkonyeni, who had been appointed to the Executive Council.
She was also a member of the Provincial Executive Committee of the ANC's KwaZulu-Natal branch for at least two terms, gaining election in 2012[9] and 2015.
[11] In June 2022, Ravi Pillay, the incumbent MEC for Economic Development, Tourism and Environmental Affairs, announced that Johnson had been appointed to chair the board of Ezemvelo.