"I feel very remorseful ... This cannot be a lawless society, I know that. I lost control but I regained control later in a holding cell," Margraves told CBS Network.
"I am no hero. My daughters are the heroes and all the other victims ... I did not think about wanting to kill him. But I did want to inflict some pain."
He added that he was "a little bit embarrassed" by what had happened.
As he spoke out, supporters started a GoFundMe page for Margraves which has raised more than NZD$42,000 as of Sunday morning.
Cunningham, who had the authority to jail Margraves for the incident, released him without punishment as she took into account the circumstances of the case.
Randall Margraves attacked Nassar after he was denied of time alone with the paedophile. Photo / Getty
"I don't know what it would be like to stand there as a father and know that three of your girls were injured physically and emotionally by somebody sitting in a courtroom. I can't imagine that," Cunningham said.
"We cannot and I cannot tolerate or condone vigilantism or any other type of action that basically comes down to an eye for an eye, a tooth for a tooth."
"That's not what's best in this situation. What's best here is that we take this horrible tragedy and we learn to educate people."
Assistant Attorney General Angela Povilaitis told families in the courtroom to "use their words", before adding that violence "would not help their children".
The chaotic scenes broke after two of Margraves daughters, Lauren and Madison, had finished reading their victim impact statements.
Their sister, Morgan, addressed the court in a previous hearing.
Margraves got increasingly angry during his daughter's readings, and while most parents of previous victims had been seen burying their faces, Margraves kept his gaze fixed on Nassar.
The three sisters are among 150 sexual assault victims delivering impact statements at Nassar's sentencing.
Nassar has been sentenced to 40 to 175 years in prison.
