Between 1952 and 1978, Bengu was a teacher in his home province, Natal, where he founded the Dlangezwa High School in 1969 and became the inaugural secretary-general of Inkatha in 1975.

After falling out with Inkatha leader Mangosuthu Buthelezi, he went into self-imposed exile between 1978 and 1991, working in Geneva for the Lutheran World Federation.

He left the government at the June 1999 general election and served as South African Ambassador to Germany until 2003, when he retired.

[1] During this period, in 1975, Mangosuthu Buthelezi founded Inkatha, the political movement that dominated KwaZulu for the next two decades, and Bengu became the organisation's secretary-general.

[1] He was secretary for research and social action at the Lutheran World Federation until 1991, when he returned to South Africa during the negotiations to end apartheid.

[19] By January 1997, some 18,000 teachers had applied for voluntary severance, and Bengu, acquiescing in a common criticism of the policy, admitted that the primary effect of voluntary severance had been to retrench experienced teachers – few of whom accepted redeployment – while costing the department millions of rands.

[22] During his tenure as Education Minister, Bengu served as a member of the ANC's National Executive Committee for two terms between 1994 and 2002.

[24] Bengu served only one parliamentary term in government, declining to seek re-election to the National Assembly in the June 1999 general election.

[29] In August 1999, President Thabo Mbeki appointed Bengu as South African Ambassador to Germany.