Kumalo (82) was born in Alexandra, and made his name as a photographer for Drum.
The ANC said on Monday Kumalo's work spoke volumes, providing the international community with evidence of the brutality of apartheid.
- Watch our tribute slideshow here
As such, his work helped to mount international pressure against the apartheid regime, ANC spokesperson Jackson Mthembu said on behalf of the party in a statement.
Mthembu described Kumalo's career as "industrious and illustrious" and "journalism in the highest form".
"The ANC and the people of South Africa are forever indebted to Alf Kumalo for being at their service and striving to expose a system that was inhuman."
Mthembu extended the party's condolences to Kumalo's family and his colleagues in the media industry.
Former President Thabo Mbeki also sent his condolences on Monday, saying he was saddened by the news.
"Alf Kumalo was more than a documentary photo journalist, he was, above all, one of South Africa's eminent historians," Mbeki was quoted in a statement.
Mbeki said Kumalo's life and work was part of a national treasure which should be preserved for current and future generations.
"No one could contradict the truth of what he captured so competently through the lens."
He said Kumalo had been subjected to harassment during apartheid but had not succumb to the pressure.
"Aware that the power of his narrative was unimpeachable, the apartheid regime subjected him to constant harassment in the hope that Kumalo, a humble and tenacious man of integrity, would abandon his work or sell his soul altogether. He did not," said Mbeki.
As a self-taught photographer who became one of the best in the field, Kumalo was an example of what dedication, hard work and commitment to life-long learning can yield, said Mbeki.
In his retirement he ran and managed the Kumalo Photographic Museum in Diepkloof, Soweto.
Kumalo, who matriculated at the Wilberforce Institute in Evaton, began his working career as a journalist and photographer for Bantu World in Johannesburg in 1951. In 1956 he joined the Golden City Post as a permanent staffer.
He covered the 1976 student uprising, the state of emergency during the 1980s, the unbanning of the liberation movements and the inauguration of South Africa's first democratic government among a host of other events during a career which spanned over more than 50 years.
Despite his advanced age, Kumalo still worked professionally and ran a professional photographic school in Diepkloof.
In 2004, Kumalo was awarded the Order of Ikhamanga, an award recognising his contribution to documentary photography and journalism in South Africa.– Sapa