Emily Hand thought she had been taken hostage for a year, her father has said.
The nine-year-old Irish-Israeli girl was one of several hostages released by Hamas last Saturday as part of a truce deal between the group and Israeli authorities.
She had spent 50 days in captivity since the October 7 attacks.
On Tuesday, her father Thomas Hand told CNN they still don't know the extent of what she went through.
"She's coming out slowly, little by little. We'll only know what she really went through as she opens up," he told CNN.
Emily refers to Gaza as "the box", Mr Hand said, and had to move from house to house in the aftermath of her kidnapping.
A short video of Emily reuniting with her father on Saturday went viral.
אביה של אמילי בת ה-9: "היא חשבה שהייתה שם שנה, כשנפגשנו היא רק לחשה - 'חשבתי שנחטפת'"https://t.co/CobRW5zIWd pic.twitter.com/XlWmXChGlA
— החדשות - N12 (@N12News) November 28, 2023
Mr Hand told CNN: "All of a sudden the door opened up and she just ran. It was beautiful, just like I had imagined it, running together. I probably squeezed her too hard."
Mr Hand said the most shocking part of seeing his daughter again was that she was only able to whisper, having been conditioned to not make any noise in captivity.
And when he asked her how long she thought she was gone, she replied “a year”.
"Last night, she cried until her face was red and blotchy, she couldn’t stop," he continued.
However, he added there were signs that she was still her old self.
"The first thing she did was get a Beyoncé song on," he explained to CNN, adding she was also smiling and was starting to laugh again.