GB News currently employs four serving Conservative MPs as well as the former prime minister, Boris Johnson.
This has raised questions about whether GB News is abiding by Ofcom rules and if Ofcom is doing its job properly.
Lord Grade said rules around impartiality, fairness and accuracy are the same for GB News as for other broadcasters, including the BBC.
Sir Jacob Rees-Mogg, the Conservative deputy chairman Lee Anderson, Esther McVey and Philip Davies all host their own shows on GB News.
Sir Jacob has not revealed his salary, but Mr Anderson has recorded a Â£100,000 salary from GB News.
Former cabinet minister, Ms McVey, received Â£58,650 for her show in 2022. Husband and co-host, Mr Davies, received Â£46,203.
Mr Johnson announced he was joining the channel last month, it is not known how much he is being paid.
Lord Grade toldBBC One's Sunday with Laura Kuenssbergthat Ofcom did not "want to be in the business of telling broadcasters, licensees, who they can employ, who they can't employ".
"There are rules about elections and politicians at election time, there are very strong, clear rules, but that's not our job," he added.
"Our job is to ensure, within the rules of due impartiality, that there is plenty of choice and freedom of expression on the airwaves."
"That means some people will always be offended by stuff, but there's no rule that says you can't be offended."
Lord Grade also said he had to "be careful" when speaking about GB News as Ofcom has 14 investigations open into the channel.
Among the current probes is a look into remarks made by actor-turned-politician Laurence Fox on the Dan Wootton Tonight programme in September.
In a series of personal comments about the political correspondent Ava Evans, Laurence Fox asked: "Who would want to shag that?"
Fox and host Wootton apologised, and the former, who also hosted a programme on the channel, was sacked.
An internal investigation into Wootton, who was suspended, was announced by GB News in September.
An interview by married presenters and serving MPs Esther McVey and Philip Davies, with chancellor Jeremy Hunt, was found to have breached impartiality rules.
Sir Jacob's show is under investigation for allegedly twice breaching the "politicians as presenters" rule which means "no politician may be used as a newsreader, interviewer or reporter in any news programmes unless, exceptionally, it is editorially justified".
GB News is not the only broadcaster to employ serving politicians.
The former culture secretary Nadine Dorries began hosting a programme on TalkTV before she quit as an MP.
Labour's shadow foreign secretary David Lammy also hosts a show on LBC.
The chairman of media watchdog Ofcom, Lord Grade, has said it is not his job to tell broadcasters who to hire.