She suffered minor injuries.
Ford, 75, was driving along the California State Route 126 in Santa Paula when the driver in front of him swerved onto an embankment, TMZ reported.
TMZ reports that eyewitnesses saw Harrison driving behind the stranger when she lost control of her vehicle and wound up crashing into an embankment right off the freeway. Together, they were able to help get the woman out of the vehicle as they waited for paramedics to arrive. The California Highway Patrol, the lead agency for the incident, is investigating the cause, Alonzo said.
Ford was reportedly leaving a small airport near Santa Paula, which is often used by hobby pilots.
The actor - who is known for his fearless, heroic roles in movies like Star Wars and Indiana Jones - did not hesitate to rush to the woman's side. He was flying a 1942 Ryan Aeronautical ST3KR, a vintage World War I aircraft, at the time.
This isn't the first time Ford's lent a helping hand though. Earlier this year, Harrison was also spotted directing traffic in New York City when he was stuck in a jam at the entrance of a tunnel in midtown Manhattan.