Lockhart began her career as a child at the Metropolitan Opera in New York. She gained great impact during the 50s and 60s when she played Ruth Martin, foster mother to Timmy, in the series "Lassie" which revolved around the dog and foster boy.
Lockhart played in tens of series and films during the nearly eight decades she was active.
One of the roles was as Doctor Maureen Robinson in the series "Lost in Space" in the 60s. She played a mother and biochemist, who had become stranded in space with her husband and three children. "Lost in Space" was also her favorite project.
It was so primitive. And I really loved the relationship I had with my space family, said Lockhart in an interview with Closer last year.
Lockhart died in Santa Monica, California, of natural causes. She became 100 years old.
