Ewan Cameron spoke out yesterday as the controversial decision to appoint him chairman of the agency was criticised by walkers, who say he is more interested in protecting farmers' interests.
But Mr Cameron, former president of the Country Landowners Association (CLA), said he had ramblers' interests at heart. He also denied there was any conflict of interest in holding the post, saying: "When I was with the CLA, I was always trying to promote access ... not only trying to ram it home to CLA members, but also local authorities.
"I used to go and speak at ramblers' annual general meetings. It's something that has been on my agenda for many many years."
Mr Cameron said he could understand the impression some people might have that his "provenance is not exactly pro-access," but he was now doing a different job.
The new Countryside Agency will have to map out huge tracts of mountain and moorland, heath and common land that the Government has announced will be opened up to ramblers under right-to-roam laws.
Walkers fear this process may take years, and that landowners could retain the option of blocking access by fighting for their rights in local access forums. Final decisions will be taken by the agency.
Mr Cameron added: "I am in a different constituency now. Then I was representing a different organisation [the CLA] and while I was trying to promote increased access, that organisation decided access should be made by voluntary means. I am now in charge of an organisation that represents the countryside in government."
He said the announcement by Michael Meacher, the Environment minister, of new legal rights for walkers was a "sensible way forward and having the presumption in favour of access, must be the better route".
He went on: "It's clearer for everyone concerned. It's clearer for the walker and it's clearer for the landowner, providing the rules allow for the proper economic and environmental management of the land, then this must be the best way forward.
"I think my experience in terms of integrating access into other land uses is going to be very very useful.
"Rights of way are probably going to be much more important to more people than the rights to roam over open countryside."