Clara Harris served for 15 years for the murder, which made headlines worldwide and was seen in a television movie.
The 60-year-old left the prison on Friday.
In 2002 Harris hired a private detective who followed her husband David Harris. She suspected that he had an affair with a former employee.
She confronted her husband and lover in the lobby of a Hilton hotel in the Houston area. The fight moved outside to the parking lot, where she met him with her Mercedes-Benz and then drove over him again and again.
Her husband's daughter from a previous marriage was with her at the time of the car's killing and testified in her 2003 trial.
During the trial, Harris's attorney argued that the crime happened shortly after the fact, in an emotional and fleeting confrontation in the same hotel where the couple had married.
The crime was recorded on tape by the private detective Harris hired to document her husband's affair.
As part of her probation requirements, Harris has to wear an ankle monitor to stay and stay in the Houston area.
She was not allowed to contact her former husband's family or his former lover. She will also be tested regularly for drugs and alcohol.