Right-wing leader Thomas Sewell told a security guard to "dance monkey" before he allegedly king-hit the man outside Nine Network's building.
Sewell, 29, leader of the European Australian Movement, faced Melbourne Magistrates Court on Tuesday after pleading not guilty to assault, affray and recklessly causing serious injury over the March 2021 incident.
He is accused of punching a security guard in the head several times, outside Nine Network's headquarters in Melbourne.
He visited the office on March 1 with a cameraman and demanded to speak to someone from A Current Affair, just hours before it was due to air a segment about neo-Nazi groups featuring Sewell.
Sewell claimed ACA was showing his group to be a terrorist organisation and said the program had not contacted him for comment.
A video of Sewell speaking to camera inside the building was shown to court, where he said ACA staff were "cowards" for refusing to meet him.
The security guard then walks over and puts his hand on the camera lens, instructing the two men to stop filming and leave.
The guard, who appeared as a witness on Tuesday, told the court he showed Sewell and the cameraman an area outside where they were permitted to film, but they instead filmed near the door.
They eventually moved back, but he claimed Sewell then began playing the song Dance Monkey.
"Both men did refer to 'oh the monkey is dancing, the dance monkey'. I took that to be offensive," the security guard said.
"I said 'there's no need for any racial slurs' and then I hand gestured that I would appreciate if you would stop, I'm not a monkey."
He said Sewell king-hit him and he fell to the ground, hitting his head on the concrete, where Sewell allegedly continued to punch him.
"I was held by my jacket collar, punched in the back of the neck, then continued to be punched repeatedly while I was trying to move away from Thomas Sewell," he said.
After a few punches he said he stood up and was separated from Sewell before walking back into the building.
An ambulance was called after the guard suffered injuries including bruising and swelling to his head. He was left traumatised by the incident.
Several Nine employees gave evidence, including assistant news director Leanne Jones who said the incident made her feel "sick".
She was outside the building on a break when the brawl began and said she heard "the most horrific bang" when the guard's head hit the ground.
Sewell's lawyer James McQuillan claimed his client had acted in self-defence and was defending his cameraman.
He alleged the security guard lost his temper and grabbed the cameraman by the throat after being told "dance monkey", which the guard denied.
Mr McQuillan also accused him of "imagining" that music was played, which the guard said was "totally wrong".
Dozens of Sewell's supporters attended court or observed the hearing remotely, including far-right extremists Blair Cottrell and Neil Erikson.
Magistrate Stephen Ballek asked those on the link to turn on their cameras to view their faces, as some were hiding under pseudonyms.
One supporter said this request was abuse and another was almost removed from court after using a photo background of Hitler Youth.
Sewell, who is on bail, will return to court on Wednesday.