Biles came to Tokyo as the reigning Olympic champion in four disciplines due to mental illness, but first broke the team competition and later resigned to the all-around final.
After that, she also withdrew from the finals in jumping, needles and freestyle.
But in today's boom final she was back, and she was welcomed with great applause and cheers by competitors and others on site in the gymnastics arena.
Biles points: 14,000
After completing her program, she had a big smile on her face and got hugs from the competitors before she smiled and waved at the photographers and the others in the stands.
However, her score, 14,000, was lower than many expected and Biles looked somewhat dissatisfied when it was presented.
At the top of the results list, it became double Chinese.
Chenchen Guan won the gold, ahead of Xijing Tang.