Simone Biles says she will always "cherish this unique Olympic experience" despite her time in Tokyo being derailed by a psychological condition known as 'the twisties'.
Biles withdrew during last week's team competition, suffering from an inability to orientate herself in mid-air.
She subsequently pulled out of the all-around final, and the first three apparatus finals, returning to claim bronze in Tuesday's closing beam.
With team silver Biles leaves Japan with two minor medals, a far cry from the four golds and bronze from Rio five years ago.
"Not at all how I imagined or dreamed my second Olympics would go but blessed to represent the USA," she said in a post on Instagram.
"I'll forever cherish this unique olympic experience. Thanks everyone for the endless love and support.
"I'm truly grateful - leaving Tokyo with 2 more Olympic medals to add to my collection isn't too shabby! 7 time Olympic medalist."
The 24-year-old's pursuit of five gold medals to equal the women's record of nine was all but ended when she baulked in mid-air on her opening vault in the team competition, as the 'twisties' struck.
The disconnect between brain and body, with the consequent loss of spatial awareness, is a potentially lethal cocktail for a gymnast somersaulting at high velocity off a vault backwards.