Carey finished eighth in Sunday's vault final -- she made a mistake on the first of her two vaults -- but the American was back to her best as she won the gold medal in the women's floor exercise with a score of 14.366 at the 2020 Tokyo Olympics.
Italian Vanessa Ferrari claimed silver -- her first Olympic medal in her fourth Games -- while bronze went to Angelina Melnikova of the Russian Olympic Committee and Japan's Mai Murakami.
"Coming back from a day like yesterday, I'm really proud of myself for being able to put that behind me and finish with probably the best floor routine I've ever done in my life," Carey told reporters as she reflected on the difference in her vault and floor performances.
"Yesterday was very tough for me," added Carey. "I tripped, I guess, in my hurdle, or right before. I don't even know. It's kind of a blur now. It was really hard, but I'm glad I'm safe and healthy. Doing that second vault, it was a challenge, but I didn't want to give up. For tonight, I just had to let that go and give it my all."
'All we've ever dreamed of'
According to Carey, all her USA gymnastics teammates were supportive of her after the vault final, but that Biles "especially" helped the 21-year-old gymnast "let it go and move on."
"She said: 'It happened, and you can't do anything about it.' She was like, 'Let's go out and kill floor,' and that's what I did."
Carey is coached by her father Brian, and the American gymnast said having him at the Ariake Gymnastics Centre meant "everything" to her.
"This is all we've ever dreamed of," said the US gymnast. "It's really special to be able to get this medal with him out there by my side.
"I talked to my dad last night, and we decided together that we were just going to let it go the best we could, and both put everything we could into tonight."
Earlier on Monday, Team USA confirmed Biles would take part in Tuesday's balance beam final.
Biles -- arguably the greatest gymnast of all time -- participated in the Olympic qualifications on July 25 and then in the US's vault rotation in the women's team final on July 27 before withdrawing from competitive action, citing mental health concerns.