Kennedy smiled as the verdict was read Friday, and her mother, Ethel Kennedy, hugged other relatives in the courtroom.
Kerry Kennedy was arrested in 2012 after she swerved into a tractor-trailer on an interstate highway, and tests later revealed a small amount of a sleeping medication in her blood.
She said on the stand during the trial that she believes she accidentally took the sleeping pill instead of her daily thyroid medication. Both were set out on the counter, in similar bottles, in preparation for an upcoming overseas trip.
Prosecutors had argued that she should have pulled over once she realized something was wrong. Her lawyers argued that she never realized she was impaired until after the crash.
The jury began deliberating Thursday afternoon after a trial that started on Monday.
