Voters on Wednesday will elect councillors, who will then choose mayors to oversee municipal services, including water, sanitation and rubbish collection.
But politicians campaigning this year have also faced questions about national issues, including illegal immigration, high unemployment and crime.
The ANC lost its parliamentary majority in 2024 and formed a unity government with the Democratic Alliance, the second-largest party, and smaller parties.
In the last municipal elections in 2021, the ANC lost control of several major cities. It governs others through coalitions.
Home to nearly five million people and most of South Africa's corporate headquarters, Johannesburg is a key economic hub and a major prize for competing parties.
The city, which is governed by a fragile ANC-led coalition, has had nine mayors in 10 years.
Political instability has been widely blamed for deteriorating infrastructure, financial mismanagement and the broader decline of the "city of gold".
Burst water pipes, cracked roads, hijacked buildings, broken traffic lights, unreliable electricity and piles of rubbish have become common sights in parts of the city.
Several parties have fielded high-profile mayoral candidates and mounted extensive campaigns.
The Democratic Alliance, which is South Africa's second-largest party, has nominated 75-year-old political veteran Helen Zille.
Her campaign has included snorkelling in a large, water-filled trench, spinning a modified BMW and DJing at a local club to rally support.
"Well, the big thing is, the ANC is certainly collapsing, it is in free fall, and suddenly we don't have a competitor anymore," Zille told The Associated Press.
The Economic Freedom Fighters have turned to Dr Tlaleng Mofokeng, who recently completed a six-year term as the United Nations special rapporteur on the right to health.
Herman Mashaba, the opposition ActionSA's candidate, is seeking another term as mayor of Johannesburg after resigning in 2019 when he left the DA.
