The memorial was attended by newly appointed Minister of Police Fikile Mbalula, minister of cooperative governance and traditional affairs Des van Rooyen, SACP deputy general Solly Mapaila and Cosatu president Sdumo Dlamini.
Hani's widow said she was aware of rumours claiming that she is with the people who are protesting against Zuma's presidency.
"I went to a prayer meeting to pray for our country ... I'm from a prayerful family and when confronted by challenges, I pray ... It's scriptural to pray for our leaders," she said. "I don't belong to a faction, I'm an ANC, there's only one ANC," she said to loud cheers.
Last week opposition parties and civic movements including Save SA held protest marches around the country to demand that Zuma steps down after his Cabinet reshuffle saw the sacking of finance minister Pravin Gordhan and his deputy Mcebisi Jonas.
In apparent reference to the protest marches which drew thousands, Limpho Hani said women were raped by taxi gangs, but there was no civil march to the taxi association to demand justice. "There was no march when the Life Esidimeni tragedy occurred."
Hani said her statement was not about campaigning for votes, but to highlight the disconnect in society.
She also thanked Zuma for his support when her her daughter was battling drug addiction. "I approached him when I was experiencing challenges because, he was the last ANC member who saw my husband alive," said the widow.
Zuma had earlier led a wreath-laying ceremony in Boksburg.
Chris Hani was gunned down on 10 April 1993 outside his house in Boksburg.