The intimate photographs were shot earlier this month in the garden of the Middletons' family home in rural Bucklebury, west of London, and show the newborn prince lying peacefully in his mother's arms.
George, the third in line to the throne, is wrapped in a white blanket and is apparently asleep despite the bright sunshine.
William, 31, stands to the left of his wife in both of the photographs, with an arm around her shoulders, and they are both smiling broadly.
Kate is wearing a long maroon dress and has her hair in waves over her shoulders, while William is in his familiar 'off-duty' clothes -- jeans and a pale blue shirt with the top buttons undone.
In one of the shots, the couple's black cocker spaniel, Lupo, joins them while Tilly, a golden retriever belonging to the Middleton family, can be seen lying behind them.
In his first interview since the birth, William said George was "a rascal" and admitted that the responsibility of being a father had changed him already.
"He's a little bit of a rascal, I'll put it that way," he told CNN in an interview shown Monday.
"He either reminds me of my brother or me when I was younger, I'm not sure, but he's doing very well at the moment.
"He wriggles around quite a lot," he said. "And he doesn't want to go to sleep that much, which is a little bit of a problem."
The fact that Kate's father, and George's grandfather, took the photographs is a radical departure for the royals, who have traditionally relied on professionals for the first official shots of new additions to the family.
Little is known how much experience Michael Middleton -- the British Airways flight dispatcher-turned-businessman -- has behind the lens.
Martin Keene, head of pictures at the Press Association agency which distributed the shots, said they were impressive.
"Any photographer would have been pleased to have taken them," he said, although some observers said both photographs were overexposed and one was slightly out of focus.
