The viral video showed a legless woman sitting on the floor of a subway platform, wheelchair beside her, belongings scattered.

She had just smoked a joint on the M train, yelling incoherently at an angry straphanger who cursed her out and threatened to toss her off the train.

The cell-phone video seemed to document a sad chapter in the chaotic life of one of New York City’s thousands of mentally-ill homeless people.

What it failed to capture was this fact: 60-year-old Michelle Carter was once a millionaire.

In 2005, Carter fell into the path of an oncoming subway train, resulting in both of her legs being amputated below the knee.

Destitute, Carter sued the city Transit Authority in 2006, claiming she had been pushed onto the tracks in the Roosevelt Island station. The TA argued the mentally ill Carter was attempting suicide when she was struck by the F train, according to court records.

She apparently spent much of the next eight years on the streets, until November 2014, when the Transit Authority agreed to pay Carter a $4 million settlement. She was finally on Easy Street.

But two short years later, Carter is again penniless and back in court.

Some of the money “dried up,” some probably squandered and some given away, her lawyers believe. But a good chunk of it disappeared in a cruel twist of fate.

While sitting in Penn Station in 2015, a thief snatched her bag and fled. Inside the bag was a recently issued cashier’s check for $886,339.96, an installment payment from Carter’s legal settlement.

Carter reported the theft to cops, but claims the thief still managed to cash the check at a JP Morgan Chase branch under the corporate name “Dahgleel A. Inc,” according to a lawsuit Carter recently filed against the bank.

“She was victimized several times,” said Carter’s current attorney, Robert Unger, who did not represent her in her previous suit against the Transit Authority.

Chase failed to confirm the identity of the person who brought the stolen check to the bank, and never should have cashed it, the new lawsuit claims. The bank declined comment.