Walker also said the supermarket group had "learned a lesson in the need for proactive communication" after a BBC report found it had failed to meet all its balm oil removal pledge.
PRWeek interviewed the 37-year-old via email for the March edition of the magazine. Click here to read the full article, in which Walker discusses wider corporate purpose, the importance of PR, being a millennial boss, and making frozen food ‘cool’ again.
Walker has helped evolve Iceland’s image in a little over a year through bold environmental pledges and campaigning. This includes banning plastics on its own-label product packaging within five years, and agreeing to remove palm oil from its own products to help address deforestation in Indonesia.
The latter saw Iceland repurpose a Greenpeace animated film for its Christmas campaign, which was famously rejected for broadcast by Clearcast on the grounds that it amounted to political messaging.
Asked if he knew the film would be rejected, Walker said: "No. Not at all. And we were gutted. We had already booked the slots for our ad to be aired.
"We were devastated when we heard the outcome, but ultimately the ad reached more people than we could have dreamed of."
Walker said he was "a little overwhelmed by the speed at which things happened" after the release of the video on YouTube.
"However, I wasn’t surprised that the public felt so moved by the film and the issues raised – palm oil is everywhere and the film brings the issues of tropical deforestation to life in a very compelling way. We were able to hijack the Christmas ad conversation and move it towards raising awareness of an environmental issue, and I’m very proud of that."
The BBC investigation in January found some Iceland own-brand products still contained palm oil by the start of this year, despite the firm saying they would not. Walker said that in "some ways the BBC did us a favour": for example, by raising some errors in ingredients listings on its website, which were "promptly corrected".
"Sometimes when you try to do the right thing, there will be someone trying to trip you up, and that’s such a shame as it discourages other businesses from making similar commitments. We were able to set our story straight and we had nothing at all to hide – we’d fulfilled our commitment in its entirety.
"It’s fair to say, though, that we learned a lesson in the need for proactive communication."