Irvin Jim is the General secretary of the National Union of Metalworkers of South Africa (NUMSA), the biggest single trade union in South Africa. He was the spokesperson for NUMSA when it was expelled from the Congress of South African Trade Unions (COSATU) in November 2014. He is a strong critic of the ruling African National Congress, which he accuses of failing to implement the 1955 Freedom Charter, and which he blames for xenophobic violence in South Africa.
In January 2015, he toured the United States, speaking to Local 1199 of the Service Employees International Union in New York, and the Institute for Policy Studies in Washington, DC. In his Washington speech, he stated that NUMSA is a Marxist-Leninist union whose goal is the creation of a "Socialist Republic of South Africa". He accused some leaders of the ANC of supporting a "post Apartheid neoliberal capitalist South Africa with South African and multinational corporations and the South African white political community" and stated that they had "betrayed the South African revolution." He is cooperating with Mosiuoa Lekota of the Congress of the People party, and ousted COSATU general secretary Zwelinzima Vavi in a campaign against political corruption in South Africa.