Hall admitted his guilt in court in mid-April, but the information couldn't be made public for legal reasons until Thursday, when reporting restrictions on the case were lifted.
The guilty plea prompted the BBC to say it was "appalled" by his actions and to say he would "no longer be contracted" as a broadcaster.
BBC human resources director Lucy Adams told BBC Radio that the allegations against Hall were "sickening" and had shaken the broadcaster to its core.
"These historical allegations are clearly very, very damaging and are very saddening, primarily for the victims," she said.
She was referring not only to Hall's case, but to earlier revelations that the late BBC presenter Jimmy Savile was a serial child sex abuser whose crimes went unpunished during his lifetime.
Hall's lawyer Crispin Aylett said Hall is "sorry for what he has done" and wishes to apologize to his victims.
"He is only too aware his disgrace is complete," Aylett said.
Prosecutor Nazir Afzal said Hall was "an opportunistic predator" who was prosecuted because "the evidence of the victims clearly established a pattern of behavior that was unlawful and for which no innocent explanation could be offered."
He said the victims didn't know each other and that nearly two decades separated the first and last assaults. He said all the victims, including a 9-year-old girl, "provided strikingly similar accounts."
The prosecutor said one victim who claimed to have been raped by Hall decided not to give evidence in the case in light of the guilty pleas that Hall had already entered.
"We have concluded that it would not be in the public interest to take steps to make her give evidence in court," Afzal said. "As such, we will not be proceeding with this charge."
Hall is one of several well-known entertainment and media figures charged with sex crimes committed decades ago.
He will be sentenced June 17.