Prince of Wales says he will stop talking about topics he feels greatly when he becomes king, "it's not that stupid".
For issues like the environment, he has been campaigning for decades, but he says he would not do the same thing as the monarch.
Prince Charles, in a BBC documentary speech to mark his 70th birthday, said he would continue mediating, "nonsense".
He said that he would have to act within the "constitutional parameters".
He ran a campaign for questions, including the environment, conservation of wildlife, architecture and the use of genetically modified crops.
In an hour long program, he was asked what some people called "interfering," but he said he always tried to stay "impartial political".
He said: "I think it's important to remember that there is only one authority at the moment, not two.
"So you can not be the same as the ruler, if you are a Prince of Wales or an heir.
"But the idea, somehow, that I will go the same way if I have to succeed is a complete nonsense, because both of them are completely different."
Asked whether his public campaign would continue, he said: "No, it will not. I'm not so stupid.
"I realize that this is a stand-alone exercise. Of course, I fully understand how this works."
Film maker John Bridcut, who had followed the king for twelve months, said Prince Charles "took some time off" using the word meddling and instead preferred to think of his interventions as "motivating."
To the successor to the throne he said: "If it interferes with taking care of places like I did 40 years ago, then, if this is an interference, I am proud of it."
Nicholas Witchell, a royal correspondent
He spent his adult life trying, as he says, to "make a difference". It has often led Prince Wales to talk about topics he feels deeply: the environment, genetically modified crops, indoor sites, architecture, education, homeopathic medicine, and others.
Prince Charles was accused of "interfering". Sometimes it caused irritation in government offices that had to respond to their hearts "black spiders" of handwritten scripts, which are always persistent, but often persistently, some questions that came to the prince.
Everything has caused greater concern. Does Prince Charles fully appreciate that these interventions will have to cease when he succeeds his mother and becomes the British king?
Those who have known him for several years have said that he understands that there is a line which, as a sovereign, could not cross.
They said that he fully understands that he should, as a king, stop his "campaign".
Prince Charles himself always spoke by speaking publicly. Obviously, any reference to how he would act as a monarch would be regarded as disrespectful for his mother.
But with the queen, now at the age of 93, and with Prince Charles, to celebrate his 70th birthday, he finally said – publicly and explicitly – to admit that his interventions in matters of public debate would stop right away, when he becomes king.
"You're acting," says the BBC documentary, "within constitutional parameters".
It is reasonable to assume that his assurances will be questioned with some relief in Whitehall and power corridors.
"He is brilliant"
Mr Bridcut said: "People who think he hangs, craving for the king are very wrong.
"This is not something that dies to take over because it will inevitably appear only after his mother's death."
He added that Duchess Cornwall, who is also interviewed in the documentary, "points out that this burden does not weigh heavily on his shoulders".
The BBC was the exclusive access to Prince Charles, who was 70th on November 14th.
The program also featured the Duke of Cambridge, who says that he would like his father to spend more time with his grandchildren – Prince George, Princess Charlotte and Prince Louis.
Prince William said, "When he's there, he's brilliant," but "we need him there as much as possible."
"People on his side"
Roger Harrabin, BBC Environmental Analyst
The Prince, decades ago, drew attention to human climate change. Some at that time were controversial, but now there is a scientific consensus on the threat.
On wild animals he rightly announced a great loss of species. He led a campaign against the destruction of the rainforest, and he would be pleased with the recent emphasis on the impact of farming on forests and thus on the climate.
His concern for the soil was marked by some observers, but it is now recognized that many areas face a crisis of degradation and soil loss.
In connection with these issues, the mainstream came to the future monarch.
On genetically modified crops, the prince still contradicts a scientific institution.
On other horse hobbies, such as homeopathy and architecture, he expressed his opinion and not the fact – but he will still have some people on his side.
- Prince, son and successor: Charles At 70, will be on Thursday, November 8, at 9 pm on BBC One.