Wanda Barzee, who pleaded guilty to helping Brian David Mitchell kidnap Smart, then 14, from her Salt Lake City home in 2002, apologized to Elizabeth's family during the sentencing hearing in Salt Lake City.
"I know the gravity of my crimes and how serious they are," said Barzee, 64. "I’m just so sorry again for all the pain and suffering I caused upon the Smart family."
Earlier, Smart's mother Lois had scolded Barzee, telling her, "What you did to Elizabeth and our family was wrong and evil."
"You hurt our family in ways you’ll never know," Lois Smart said. "It was unconscionable what you did to [Elizabeth]. I hope you will be able to make peace with your maker."
U.S. District Judge Dale Kimball gave Barzee seven years of credit for time she has already served and ordered her to spend the rest of her term at a medical and psychiatric center for female federal prisoners in Texas.
In exchange for the sentence, Barzee agreed to testify against Mitchell, whose trial is slated to begin this November.
Mitchell, 56, is accused of abducting Smart at knifepoint from her bed and forcing her to become his plural wife. Smart was held for nine months by Mitchell and Barzee in the Salt Lake City foothills and San Diego area before their arrest in 2003 when they were spotted walking with Smart in a Salt Lake City suburb.
After the hearing, Elizabeth's father Ed Smart said his daughter didn't feel that Barzee's sentence was "strong enough."
"It is what it is," he said with a sigh. "We’re just glad this part is over."