“He was looking for a job but did not have a matric,” African National Congress spokesman Keith Khoza said.
“He said he came to [Luthuli House] because the ANC was in government.”
Khoza said the man hit the Luthuli House glass doors with a piece of wood on Thursday.
The man was not an ANC member.
Gauteng police spokesman Lt-Col Lungelo Dlamini said Luthuli House security guards caught the man and then handed him over to the police.
He said he could not confirm that the man was upset with the ANC because he did not have a job.
“The motive will be heard when he appears in court,” he said.
The man was expected to appear in the Johannesburg Magistrate’s Court later on Friday.