Prince Harry let his family down when he was pictured naked in a Las Vegas hotel room last year, he has said.
But he said his treatment by the press over the photographs was not "acceptable", as he was at a party where he had expected privacy.
The images of the prince were published on the web and by the Sun last August.
The 28-year-old was speaking just before he completed a four-month deployment to Afghanistan in his role as an Apache helicopter pilot.
The pictures of Prince Harry and a young woman naked appeared on US website TMZ - which reported that he had been playing "strip billiards" after inviting friends back to his hotel room for a private party.
The Sun printed the photos, despite warnings from the Royal Family's lawyers that it would be an invasion of the prince's privacy.
However, a complaint was later dropped by St James' Palace on the grounds that it would be a distraction for Harry as he began his second deployment to Afghanistan.
It is the first time Harry, who was speaking from Camp Bastion, the main British military base in Afghanistan, has talked in public about the Las Vegas incident.
He said: "At the end of the day I probably let myself down, I let my family down, I let other people down.
"But at the end of the day I was in a private area and there should have been a certain amount of privacy that one should expect."
He added: "It was probably a classic example of me probably being too much Army and not enough prince. It's a simple case of that."
He said some people considered it a chance for "letting off steam" ahead of his Afghanistan deployment.
"Well, the papers knew I was going out to [Afghanistan] anyway, so the way I was treated from them, I don't think is acceptable."
In 2008 the prince's first tour was cut short after a news blackout about the deployment collapsed, raising fears he would be targeted by the Taliban.
News teams were allowed to interview him during this tour, while agreeing to delay broadcast until he had left the country.
'Country comes first'
The prince described himself as having three parts to his life: "One in the army, one socially - my own private time - and one sort of with the family and stuff like that. So, you know, there is a switch and I flick it when necessary.
"And I like to think it's measured and balanced... Army comes first - it is my work at the end of the day.
"Whenever anybody sees me they presume that I'm off... gallivanting around. I don't want to sound as if I'm whingeing but there are times when doing all the army stuff and doing public engagements and stuff like that... is exhausting, and people criticise me."
He said his brother, Prince William, an RAF pilot, shared his view that "our service towards our country in the military - whichever shape or form it takes - will always come first".
Captain Wales, as the prince is known in the military, arrived for his second tour as part of the 100-strong 662 Squadron, 3 Regiment, Army Air Corps in September.
During his UK absence, Prince William and the Duchess of Cambridge announced they are expecting their first child - although Catherine's medical condition prompted them to do so very early in her pregnancy.
Prince Harry said: "Obviously I'm thrilled for both of them. It's about time. I can't wait to be an uncle.
"I think it's very unfair that they were forced to publicise it when they were, but that's just the media for you.
"And I literally am very, very happy for them, but I just only hope that she and him, but mainly Catherine... gets the necessary protection to allow her as a mother-to-be to enjoy the privacy that that comes with."
The full interview will be broadcast on BBC News Channel at 22:30 GMT, 21 January 2013.