Childhood doctors initially thought Amoruso had Tourette's syndrome. She would later be formally diagnosed with attention deficit disorder.
Amoruso's frenetic energy and "bad attitude" have served her exceedingly well. She is the only millennial newcomer to this year's Forbes Richest Self Made Women list not from the entertainment industry.
The list pegs her personal worth at a whopping $280 million. She ranks ahead of Beyonce and Taylor Swift. Her company, Nasty Gal - which sells a mix of high end, retail and vintage clothing - reportedly makes around $300 million a year.
The rags-to-riches story of Amoruso's rise to success reads like a Hollywood movie script. (In fact, Netflix has a television series based on her life in production now. Friend Charlize Theron is one of the Executive Producers).
After watching her parents go bankrupt and leaving home at 17, she worked in just about every job you can imagine from Subway sandwich artist, to bookstore assistant at Borders. There was a stint at a hydroponic plant shop balancing PH levels. She also tried selling orthopedic shoes and working at a drycleaners.
Young Amoruso's life lacked both direction and the funds to change that. She was resorting to dumpster diving and shoplifting to make ends meet. It wasn't until she was caught stealing a George Foreman grill (yes, really) that she decided it was time to grow up.
Amoruso packed up her stuff, moved to Portland and bought a copy of "Starting an eBay Business for Dummies".
This millennial business icon happily agrees with my labelling of her fledgling vintage eBay store, Nasty Gal, as "scrappy". "I didn't have any grand aspirations," she discloses. "I wanted to make some money doing something I thought was fun".
Nasty Gal was named after the 1975 Bette Davis album. "I loved how she had reclaimed the word 'nasty' as something empowering," Amoruso says.
"No one could tell her what she was or wasn't, and so what if you did - she was going to interpret that however she wanted. That disregard for rules and definitions, along with her unapologetic attitude, resonated".
Nasty Gal clothes are designed to appeal to the millennial belly button feminist. Stylists for the brand match leopard print crop tops with ripped denim skirts, black and gold spiked chokers and long sheer bohemian-style robes. The clothes are eclectic and modern. The wearer is unapologetic about her sex appeal. Exposed skin is a mandatory accessory.
"Why should something we do every day be considered vain or petty ..." says Amoruso.
"It's no myth that when we look good, we feel good."
When I ask Amoruso about her eye for putting awesome outfits together, she basically fobs me off. "My passion is really for building brands - the voice, the attitude, the visual representation in every form whether it be photography, design, or the fashion itself". It's unspoken but abundantly clear from her tone: Business, not fashion, is Amoruso's talent.
Amoruso applied herself diligently to mastering the very specific craft of eBay selling. She learned how to style clothes so they were most attractive in a teeny, tiny photo and how to pair low-end with high-end pieces to show them off to maximum advantage.
With only 55 characters available to describe each product, Amoruso had to be disciplined. Every word and every image had to work hard.
She became a slave to yard sales, rag houses and rummaging through donation bins to find treasure that other people had mistaken for trash. Bidding wars weren't unusual at Nasty Gal, with customers driving prices higher and higher such was the desire to own one-off vintage items.
Amoruso once bought two Chanel jackets for $8 each. The pair sold for more than $3000.
In 2008 Amoruso abandoned eBay and launched Nasty Gal as a stand-alone website. She sold out her entire stock on day one such was the size and dedication of her following.
Success has come quickly but the decisions haven't always been easy. "It's always been a long series of taking risks," says Amoruso. "The day I signed the lease on our first office space and we finally moved out of my apartment was pretty intense. And scary."
As the business grew and grew, Amoruso was careful to remain faithful to her original vision. "Advice and input starts coming at you by the bucketful," she tells me. "You have to be ready to sort through all of the crap in order to find the useful stuff, even from the most experienced advisers, investors and executives".
Authenticity, business commentators insist, has been the key to Amoruso's success. She's 100 per cent true to herself. This is her style, her brand and her vision. Unlike other major fashion houses that market to millennials, Amoruso doesn't need to hire experts to tell her who the consumer is. She is the consumer herself.
With a very visible public profile, Amoruso is not just the founder but also the living embodiment of her now-global brand. That isn't without its challenges. Especially when there have been media reports about Nasty Gal, which run directly counter to the brand's values.
In 2015 there were a series of major lay-offs at Nasty Gal and four former employees brought a discrimination lawsuit against the company. They claimed they'd been fired for getting pregnant. Nasty Gal denied the accusations.
Anonymous online comments from users purporting to be Nasty Gal employees paint a pretty, well, nasty picture of what it's like to work there. One comment read: "The PR and hype can't mask what's really going on here. You drink the kool-aid for the first few months working here, then start to realise it's all just smoke and mirrors".
Some have linked this criticism to Amoruso stepping down as CEO of Nasty Gal soon afterwards (she remains majority owner) to focus on her book #GirlBoss and related endeavours.
#GirlBoss, was released in 2014 and spent a whopping 18 weeks on the New York Times bestseller list. A true digital native, including a hashtag in the title of her part-memoir, part-business-how-to-manual was the author's idea.
The book has become an online movement. There is a podcast, a website, a conference and a TV show in the pipeline. And so the empire continues to expand ...
So much has been said and written about Amoruso that it can be difficult to untangle the fact from the fiction. I ask her what qualities she credits as the biggest contributors to her success. "Persistence. Hours. Curiosity," is her response.
Sheer determination is certainly something this Girl Boss possesses in abundance. Amoruso said in an interview with Forbes once that you shouldn't start a business if you can't give it everything, every day for the foreseeable future. So much for work-life balance, hey?
I ask her if she thinks that's realistic for most people. Amoruso responds with her trademark authenticity: "No. Successful entrepreneurs are not regular people. You have to be unbalanced."
