City of Tshwane Mayor Solly Msimanga will officially vacate his office next month and focus on winning the hearts of Gauteng residents ahead of the national elections instead.
He confirmed his resignation at a media briefing at the DA's Johannesburg headquarters on Friday.
Msimanga said he agreed to resign when asked to do so to focus on his bid to unseat the ANC in South Africa's economic hub.
"I cannot serve the people of Tshwane if I'm running a campaign," Msimanga told journalists.
READ: Solly Msimanga to step down as Tshwane mayor
Counting several of his achievements in office, including the removal of 900 ANC political appointees who were earning millions from the City, Msimanga said the people of Tshwane could only have a better life if Gauteng was also under DA leadership.
"No matter how hard we can work, unless we turn the whole province around, it would make no difference."
DA billboard
The DA also defended its election poster, titled 'The ANC is killing us', which lists the names of the victims of the Marikana and Life Esidimeni tragedies, along with the names of children who died after falling into pit latrines.
In the Life Esidimeni tragedy, 144 psychiatrist patients died after they were transferred from the mental health facility
When Msimanga was asked what he made of the reaction from relatives of Life Esidimeni victims, he said he was always willing to listen and added that the DA would approach the families.
"We do need to hear cries whenever there might be cries, not be tone deaf and [we must] be able to be responsive as well," he said.
WATCH: Angry Life Esidimeni victims' relatives tear down DA billboard
But DA leader in Gauteng John Moodey, said the billboard was going nowhere.
"Of course we care about the views of the family. We are not discounting it. However, the billboard reflects the sad and hard truth of what we South Africans face," said Moodey.
He said people died because of an uncaring government.
"That billboard will stay up for the duration which we've contracted it to be," he said.
The elections are scheduled for May but a precise date has not yet been announced.