Genevieve Sabourin was released from Rikers Island in New York, reported Contactmusic.
"Ms Sabourin is ready to move on with her life and put this all behind her," her attorney, Todd Spodek, said.
She had been ordered to spend 180 days behind bars in November last year after she was found guilty on five counts of harassment and stalking.
The charges were filed after she bombarded the '30 Rock' star with emails and voicemails and made unwelcome visits to his Big Apple homes after enjoying a meal with him in 2010.
Sabourin's sentence also requires her to stay away from Baldwin and his family following her prison release.