The Duke of Cambridge said his spaniel Lupo was "coping alright" with the new addition to the family.
Prince William said, "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."
The Duke of Cambridge said although the moment he and his wife left the hospital with their newborn son was daunting, "We were happy to show him off to whoever wanted to see him".
Prince William said the last few weeks have been "a very different emotional experience" and "something I never thought I would feel myself."
The Duke of Cambridge said he is "just doing it the way I know" rather than trying to be a symbol of a modern monarchy.
Asked whether the moment he and his wife showed their newborn son the world was an example of the monarchy's modernisation, he told CNN, "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."
William said he, his wife and Prince Harry have grown up "differently to other generations".
"I very much feel if I can do it myself I want to do it myself," he continued. "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."
The Duke of Cambridge said his son Prince George is "a little bit of a rascal" and "a little fighter" in an interview with CNN.
Describing the newest addition to the royal family, Prince William said, "He either reminds me of my brother or me when I was younger."
He said George "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 added.