Michelle Carter, 22, was convicted of involuntary manslaughter and sentenced to 15 months in prison in 2017.
She was allowed to remain free while she appealed her conviction. The Massachusetts Supreme Judicial Court upheld her conviction last week, saying that her actions caused the death of her then boyfriend Conrad Roy III.
Carter was 17 in July 2014 when she persuaded Roy, 18, to kill himself through dozens of text messages and phone calls, prosecutors said.
Roy died when his pickup truck filled with carbon monoxide in a store parking lot.
After she convinced Roy to kill himself, she did absolutely nothing to help him: she did not call for help or tell him to get out of the truck as she listened to him choke and die, the state's Supreme Judicial Court Justice Scott Kafker wrote.