Kaizer Nyatsumba has quit as CEO of the Steel and Engineering Industries Federation of Southern Africa (SEIFSA), the entity announced on Friday.
Prior to his departure, Nyatsumba was placed under precautionary suspension in May, although the charges were not made public. The federation said the suspension was later lifted, but the parties had resolved to part ways.
"Due to recent events, the parties reached an agreement to mutually separate," said a statement.
It is understood that Nyatsumba plans to return to his consulting business.
SEIFSA previously said the board had commissioned a private investigation into Nyatsumba's conduct at a special board meeting on 15 June.
Nyatsumba, a former newspaper editor, had earlier said that the board's decision to suspend him following his hospitalisation had "surprised and shocked" him and was "totally unexpected".
He joined SEIFSA on 1 November 2013 as chief executive officer and has been at the helm during a period that has seen the industry face a steady decline.
"Throughout my working career, I have done nothing that has ever been worthy of an investigation, and I have absolutely no doubt that, at the end of it all, I will be vindicated," Nyatsumba previously said.
"Over more than three decades, I have worked very hard, across different industries, to build a career based on honesty and unimpeachable integrity. I don’t know if everybody can say the same."
SEIFSA represents 19 independent employer associations in the metals and engineering industries, and Operations Director Lucio Trentini and CFO Rajendra Rajcoomar have been in charge of the running of the organisation in Nyatsumba's absence.