updated 01/23/2014 AT 11:00 AM ET
•originally published 01/23/2014 AT 3:30 PM ET
She’s now making headlines for taking Johnny Depp, one of the world’s most eligible bachelors, off the market, but back in her hometown of Austin, Texas, Amber Heard stood out for her ambition – and her brains.
“Very early Amber understood beauty only opens the door of opportunity,” agent Jeff Nightbyrd, of Acclaim Talent, Inc., tells PEOPLE.
“She wanted the ability to grab the opportunity by the throat and prove she had the substance to back up her looks,” he says. “I would argue Amber Heard is a Katharine Hepburn in a different kind of body.”
As Heard’s first agent in Austin, Nightbyrd signed the actress when she was 16.
Well before she met Depp on the set of The Rum Diary, Heard set herself apart with her “street savvy, curiosity, originality and an incredible willfulness,” says the agent.
“She wanted to know what she needed to learn to be successful,” Nightbyrd says. “Her contemporaries wanted to be pop stars.”
Heard, 27, first hit the big screen in 2004’s Friday Night Lights, while off screen she has been outspoken about everything from being bisexual to loving muscle cars and book collecting.
Her dedication to her career – she and Depp, 50, will appear together again in the upcoming film London Fields – is something that Nightbyrd finds distinctive about her.