Speaking four weeks after the birth of his first child George Alexander Louis, who is third in line to the throne, William described him as "a little rascal".
"So he either reminds me of my brother or me when I was younger," he said.
The Duke said that although the moment he and his wife, Duchess of Cambridge, left the hospital with their newborn son was daunting, "we were happy to show him off to whoever wanted to see him".
It comes as the first official photos of Prince George have been released by Kensington Palace.
The intimate pictures were taken by Kate's father Michael Middleton in the garden of the family home in Bucklebury, Berkshire, earlier this month.
The Prince said he wasn't allowed to shirk from his fatherly duties such as nappy-changing either, as he said he had midwives watching over him.
"They were saying 'you do it, you do it'," he laughed.
He added that George "is a little fighter".
"He wriggles around a lot, he doesn't want to go to sleep that much, which is a little bit of a problem," and that his wife was "doing a fantastic job".
"At the moment, the only legacy I want to pass on to him is to sleep more and maybe not have to change his nappy so many times," William said.
He also admitted the last few weeks have been "a very different emotional experience".
"Something I never thought I would feel myself," he added.
And I find, again it's only been a short period, but a lot of things affect me differently now.
The Duke said their spaniel Lupo was "coping alright" with the new addition to the family.
"As a lot of people know who have got dogs and are bringing a newborn back, they take a bit of time to adapt, but he's been alright so far."
When asked about the role of being a future king, he said he was "just doing it the way I know".
He said the decision to take his wife and baby home himself was something he wanted to do.
"I'm reasonably headstrong about what I believe in, and what I go for, and I've got fantastic people around me who give me great support and advice," he said.
"I very much feel if I can do it myself I want to do it myself. There are times where you can't do it yourself and the system takes over or it's appropriate to do things differently, but I think driving your son and your wife away from hospital was really important to me."
Although he admitted he had to prepare himself to be able to fit a car seat so quickly in front of the world's press.
"Believe me, it wasn't my first time," he said. "I had to practice, I really did. I was terrified that it was going to fall off or the door wasn't going to close properly, so I had actually practiced with that seat."
Prince William said he was looking forward to getting back to work so he could avoid a few "night shifts" with baby George.
The full interview with the Duke of Cambridge is due to be screened on UTV next month in the documentary 'Prince William's Passion: New Father, New Hope'.
Catherine and Prince William pose with their son, Prince George Alexander Louis of Cambridge, surrounded by Lupo, the couple's cocker spaniel, and Tilly the retriever in the garden of the Middleton family.