Harry's comments come after he delivered an impassioned speech at the Kyiv Security Forum on Thursday in which he appealed to Russian President Vladimir Putin to "stop this war" and urged "American leadership" to honour its obligations in the Ukrainian conflict.
The Duke of Sussex, who served on two frontline tours to Afghanistan, also said he was "not here as a politician" but as "a soldier who understands service" and a humanitarian, echoing remarks made by his late mother Diana, Princess of Wales, in 1997 during a trip to Angola.
In Ukraine on Friday, Harry told ITV News he does not recognise the description of himself as "not a working royal".
He said: "I will always be part of the royal family and I'm here working and doing the very thing that I was born to do, and I enjoy doing it.
"I enjoy being able to do these trips and come and support the people that I've met before, the friends that I've made, and hopefully bringing attention to issues that for one reason or another drop out of the news because something else has popped up."
Harry's trip comes just days before his father King Charles begins a major state visit to the United States to see President Donald Trump against the backdrop of trans-Atlantic tensions over the Iran conflict.
Asked if he believes any of the comments he has made during his time in Ukraine will affect the state visit, he said: "Not at all."
The duke also referred to his mother's trip to Angola in 1997 to campaign against landmines.
During her visit, Diana said: "I am not a political figure. I am a humanitarian figure and always have been and always will be."
On Friday, Harry told ITV News: "It's very, very sad because nearly 30 years ago since my mother was in Angola here we are again in a new conflict."
It was a rare input on global matters from the duke when he implored the US to "honour its international treaty obligations" in its "enduring role in global security" during his speech in Kyiv.
Responding, Trump said: "I know one thing, Prince Harry is not speaking for the UK, that's for sure. I think I am speaking for the UK more than Prince Harry.
"But I appreciate his advice very much."
But Harry has said people need to "speak up".
"As a global community we need to feel empowered to be able to speak truth to power. It's really that simple," Harry told ITV News.
"It's bad enough in today's world feeling gagged and saying that you can't say these things and can't say that and everything becomes political. I fundamentally disagree with that.
"What we are witnessing and what we are seeing is a humanitarian catastrophe in multiple parts of the world and people are speaking up and people will continue to speak up and I would encourage more people to do the speaking up."
Harry's unannounced visit - his third trip to Ukraine since the war began in 2022 - comes days after he finished a tour to Australia with his wife Meghan.
