She told DailyMail.com she was checking and returning work emails so she didn't see the Cadillac approach.
"My first thought was 'This is not happening to me today' and I guess my first reaction was to jump on of the car,' Smith said.
"I just has zero thoughts about how they could hurt me."
Smith, seen in red, instinctively jumped onto the hood of her SUV to prevent the vehicle from being driven off.
The driver is seen abruptly breaking twice in an attempt to throw Smith off the vehicle.
"I realise as this was happening that, 'Okay, I could be going for a ride and I better think of when I should be getting off'," she said.
Smith said the thief then grabbed her purse off the floor and got out of the SUV - leaving it in gear - and jumped back into the getaway car. And although Smith wanted to run after him to get her purse, she knew she had to stop the car.
"I realised my car was still moving. So I tried to stop it, but I obviously I couldn't," she said.
"So I had to hop in and I managed to stop it just before it hit a light post."
The suspects are still at large, but police who arrived on the scene fingerprinted Smith's car.
They also told her that the Cadillac they drove up in was itself stolen earlier that day.
She shared video of the incident both to warn her larger network about carjackings and to send a message to teenagers possibly involved in this type of behaviour.
"I think teens do it because they think it's cool," Smith said.
"But it's just like you get told by your mum when you're a kid, 'If everyone else was jumping off a bridge, would you do it too?'"
"It will not make you good, honest money. It will not make your life easier, it will only make it harder."