Oral evidence in the first part of the inquiry into media ethics and phone hacking could start next month, Lord Leveson said today.
In a preliminary hearing for the inquiry, he said the evidence, which is likely to be televised live, could start as soon as the second week in November.
The first part of the inquiry will look at the culture, ethics and practices of the press and its relationship with the police and politicians.
In preliminary discussions at the High Court today, Lord Leveson said: "The present thinking is, and I am not committing to this, that we are unable to be likely to start before the second week in November."
He told the hearing he originally wanted to press for a slightly earlier start, because of the "territory that has to be travelled before next summer".
The Leveson Inquiry, announced by David Cameron in July, aims to produce a report within a year.
"I am not going to be overly constrained but I am very keen to keep the focus because I am conscious that whatever I come up with is likely to generate a debate," Lord Leveson said.
"A debate among the media, who may or may not be polite, a debate among the political groups and a reconsideration of the way, perhaps, regulation or self-regulation, whatever comes out, is organised, which everybody is going to want to get on with.
"Which is why this part of the inquiry has to be before the normal timing which is when the police have finished whatever they want to do.
"It strikes me that the imperative is not merely a pressure to do what I have been asked to do, it is because it is actually very important to achieve something, broadly within from what is now about a year."
He said he could take three years, or five years, but added: "But I am not sure that serves the interest of the public."
Lord Leveson said the inquiry was different from other probes generated by specific events such as the Hillsborough disaster.
"The first problem is that a lot of precise detail which is normally the starting point for an inquiry is, or may be, tied up in the investigation being undertaken by police.
"Therefore to some extent, as has been observed and I have said, the inquiry puts the cart before the horse because if I were to wait for the police investigation it would not start in a time to be measured in not weeks, and not months, I don't know."
He said he would be taking advice from the Director of Public Prosecutions about how "far" he could go, without prejudicing the police investigation.
Lord Leveson repeated assurances that the inquiry will be "open, transparent and fair", and again encouraged everyone involved to work together.
The hearing was told some newspapers had produced material required for the inquiry on time, while others had requested extensions, and Lord Leveson said he was grateful to both.
"Everybody has got to help, I am very sorry but that's the nature of the beast and it isn't in anybody's interest that this takes longer than it need take.
"There are issues which have to be addressed and we have all got to address them and to that extent if different groups have different ways of working and want to suggest approaches then I am very prepared to receive them."