He was first elected to the National Assembly of South Africa in 1999 as Member of Parliament for the African National Congress. He resigned in 2001 but was elected to the National Assembly again in 2004. President Thabo Mbeki appointed him to the position of Deputy Minister of Home Affairs. President Jacob Zuma appointed Gigaba as Minister of Public Enterprises, succeeding Barbara Hogan in October 2010. He served in that position until 2014, when he was appointed Minister of Home Affairs. Gigaba was appointed Minister of Finance in March 2017 after the controversial dismissal of Pravin Gordhan.