Mr Griffin has complained the Question Time audience was like a "lynch mob"
The British National Party could be invited to appear on Question Time about once a year, BBC director general Mark Thompson has suggested.
Speaking to the Lords communications committee, Mr Thompson said audiences should ask questions of "politicians from across the political spectrum".
He added that "objective criteria", such as levels of party support, were used when choosing panels for the show.
The BBC faced angry protests for asking BNP leader Nick Griffin on to the show.
Mr Griffin complained he had been the victim of a "lynch mob" after he was criticised by the studio audience and other panel members on Thursday's programme and called on the BBC to give him a second chance to appear.
The programme was watched by 8.2 million viewers - far higher than its normal audience.
But speaking to the committee, Mr Thompson said of the BNP leader's appearance: "No part of this decision-making related to a desire to increase ratings."
He added that the BBC had invited Mr Griffin on, and that the party had made no formal application to him.
Mr Thompson said he believed "that the objective criteria that we would typically look to be fulfilled if we were inviting a minor party onto Question Time had been fulfilled.
"And on the basis of that we decided to extend the invitation."
As with other smaller parties, "there will be occasions where it feels right to invite them (on the) programme", Mr Thompson said.
Asked how often the BNP might appear on Question Time, he said: "I would say that we're talking about, in the case of a party which... if it continued to receive that level of support, appearances (would) probably be no more than once a year and could be less."
He said he did not believe he had the authority to make a "value judgement" on whether someone's views should be heard.
He added: "Question Time in many ways parallels the democratic process itself.
"Not everyone is going to agree with everything that is expressed on Question Time. That's not how democracy works."
Six protesters were arrested and three police officers injured during demonstrations outside BBC Television Centre ahead of the broadcast.
Labour MP Mike Gapes, who chairs the Commons Foreign Affairs Committee, has tabled a Commons motion, accusing the BBC of being "profoundly wrong" in treating the BNP as a "normal party", based on their support in the European elections, where they now have two Euro MPs.
The Early Day Motion, signed by 10 MPs, says Mr Griffin's invitation to appear on the BBC's flagship political discussion programme "calls into question the judgement of BBC management" and the role of what it calls the "pusillanimous BBC Trust", which rejected calls for it to be withdrawn.