The 42-year-old was caught on camera by ITV News at the wheel of her car reversing out of a driveway before pulling away.
Ms Sacoolas, who is the wife of a US technical intelligence officer, claimed diplomatic immunity and was able to return to America after the crash outside RAF Croughton in Northamptonshire on August 27.
Harry Dunn’s family, who have been campaigning for her to be brought to justice in the UK, said the footage had left them “distraught”.
Harry’s mother, Charlotte Charles, was left in tears after viewing the footage and told the broadcaster: “(I’m) distraught to be honest.
“She’s clearly just going about her normal day, driving and taking the kids to school.
“She looks well, she looks calm, the house is all decorated with Christmas stuff – candy canes on the driveway, lights around the tree.
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“She’s just going about doing whatever she would usually do as though nothing’s ever happened.
“Her life looks so normal and she’s completely wrecked ours.”
Mrs Charles is in the US with Harry’s stepfather, Bruce Charles, and father, Tim Dunn, to press for Mrs Sacoolas’ extradition.
Radd Seigler, Harry’s family’s spokesman, said: “They are completely devastated by what they have seen and feel like they have been taken for fools. They feel like they have been naive and stupid.
“The footage taken and her demeanour clearly shows she has no intention of coming back voluntarily to the face the music, nor does she appear to have any care or concern for what Harry’s family are going through.”
The Crown Prosecution Service (CPS) was handed a completed file of evidence on November 1 after Northamptonshire Police interviewed Mrs Sacoolas in the US.
Chief Crown Prosecutor Janine Smith has previously said she will meet with Harry’s family once a charging decision has been made.
But the family has spoken of their frustration at the length of time it is taking and said they are considering bringing a private prosecution.