Some entrepreneurs focus on one business, while others get bitten by the bug and become serial business starters. ABC’s Shark Tank and CNBC’s The Profit have drawn attention to some of these high-profile people and the toughness and tenacity it takes to succeed. Let’s find out more about how these multi-millionaires and billionaires built their businesses to become the sharks who swim at the top of the tank. 

Born in Croatia, Robert Herjavec was actually a refugee to North America, escaping with his parents from war-torn former Yugoslavia at the age of eight. As a young man, he applied for a job with Logiquest selling IBM products, but was underqualified. He therefore offered to work for six months for free, and waited tables to pay his rent. Herjavec eventually became a general manager of the company, leaving to launch a computer company, BRAK Systems, from his basement. 

Reamarkably, Herjavec sold BRAK Systems to AT&T in 2000 for a whopping $30.2 million and, in 2003, launched Herjavec Group, developing solutions to cybersecurity. As well as this, the entrepreneur has worked as a film actor and assistant director, experience that may have helped with his role as one of the main cast members of ABC's Shark Tank, as well as his turn on Canada's version, Dragon's Den. According to Forbes, Herjavec is currently worth $200 million.

A straight ‘D’ student, Barbara Corcoran was working her 20th job by the time she turned 23. She decided to quit her job as a waitress and borrowed $1,000 to set up a small real estate business with her boyfriend in New York. Seven years later, Corcoran-Simonè became The Corcoran Group after she split with her partner, and this company grew into a business worth more than $5 billion.

As well as running her company, Corcoran is a commentator on real estate data trends in New York City, notably through her Corcoran Report. She is also a regular guest on NBC's Today Show, has a weekly column in the New York Daily News, and hosts The Millionaire Broker with Barbara Corcoran on CNBC. Through her role on Shark Tank, she has invested in tens of businesses. Her net worth was given by Forbes as $80 million.

Lori Greiner has made her money as an inventor. Her first product was an earrings organizer which was picked up by J C Penney in 1996 and became a huge bestseller. Since then, she has created over 700 products and holds more than 120 US and international patents in areas as diverse as organization for cosmetics and jewelry, electronics, travel items, household items, and more.

Greiner is, as you would expect, a consultant for both product design and venture capital investments. She also works as a TV presenter, which got her the nickname ‘the Queen of QVC’, and hosts her own show, Clever and Unique Creations by Lori Greiner, which has been running for nearly 20 years. Greiner is reportedly worth $100 million.

Brooklyn-born Daymond John showed an entrepreneurial spirit from a young age. He began working at the age of 10, doing jobs such as handing out flyers for $2 an hour. After high school, he started a commuter van service at the same time as waiting tables to make ends meet, but it was in 1992 that things really took off. With the help of a neighbor, John sewed 90 hats that he saw were in fashion, and sold all of these in a single day. He called his business ‘For Us, By Us’ ─ FUBU.

FUBU’s hip hop-style apparel is now sold in more than 5,000 US stores and has made over $6 billion in sales, while CEO John is reportedly worth $300 million. His investments on ABC’s Shark Tank have also enjoyed remarkable success ─ he has helped businesses such as Bubba's-Q Boneless Ribs, Bombas Socks, and Sun-Staches eyewear go from thousands to millions of dollars in sales.

A stalwart of the Shark Tank line-up since Season Two, Mark Cuban has always shown he has a business head on him. As a child, Cuban made money selling garbage bags door to door, a work ethic he maintained when he went to college where he worked as a bartender, disco instructor, and party promoter. But he really started to prove himself in 1983, when he founded MicroSolutions, a system integrator and software reselling business, which he then sold to CompuServe only seven years later for a cool $6 million. He then co-created an online streaming audio service, Broadcast.com, which he sold to Yahoo! in 1999 for $5.7 billion in Yahoo! stock.

Cuban didn't stop there. After this, Cuban moved into film and TV, with distribution company 2929 Entertainment, arthouse cinema chain Landmark Theaters, as well as AXS TV and Magnolia Pictures. Not only that but, like many successful super-rich people, Cuban has bought a sports team, and is the owner of NBA’s Dallas Mavericks. His net worth is reportedly $4.1 billion.

Longtime Shark, and former Canadian Dragons' Den resident, Kevin O'Leary seems to have inherited his business acumen from his mother, although he only found out about her large investment portfolio after she had died. The apple didn't fall too far from the tree, however, and from an early age he had adopted her habit of saving and, after his studies and a brief career as a TV producer, he collaborated with two of his former MBA classmates to create Special Event Television (SET). However it was after selling his share to a partner that O’Leary achieved real success, with SoftKey.

Like many tech start-ups SoftKey was established in a basement, but went on to become a leading educational software company. O’Leary sold it to Mattel in 1999 for $4.2 billion. But money started to get serious after he co-founded StorageNow, which later sold for $110 million. Other businesses followed dealing in funds, ventures, mortgages, books, and even wine. Reportedly worth $400 million, O'Leary's blunt manner has led him to be given the ironic nickname Mr. Wonderful.

John Paul DeJoria is the son of Greek and Italian immigrants, however his parents divorced when he was two. He and his brother worked selling Christmas cards and newspapers when DeJoria was just nine. Sadly, his mother could not support them and they were sent to live in a foster home. After two years in the navy, DeJoria then held a series of jobs such as janitor and door-to-door salesman of encyclopedias and insurance. But  in 1980, he borrowed $700 and co-founded John Paul Mitchell Systems.

24 people who were born poor but went on to make billions

At the time, DeJoria was homeless and sleeping in his car while selling shampoo door to door. However, this business took off, and is now a global success. DeJoria went on to co-found both the Patrón Spirits Company in 1989 and the House of Blues nightclub chain in 1992, and is invested in many other businesses including Ultimat Vodka, Touchstone Natural Gas, and Diamond Audio. DeJoria has come a long way from the days of living in his car, and is now worth a mighty $2.6 billion according to Forbes.

Chris Sacca's story is not a typical rags-to-riches tale, with a mother professor and father attorney. However, it's not without drama. He may be one of the youngest on Forbes’ Midas List, but after the failure of his first business Sacca used the remaining funds to begin trading on the stock market to great success, at first. But when the stock market crashed, Sacca found himself lumbered with a huge $4 million of debt. As a trained attorney, Sacca refused to declare bankruptcy as he was concerned it would affect his credibility. So, he worked his day job and took up extra research work to pay off his debt.

But he had another setback when his firm was making cuts and he was fired. Instead of panicking he set up The Salinger Group, faking it until he made it, and picked up consultancy work. This attracted a big client: Google. While there, he paid off his debt and began investing his cash as an ‘angel investor’ into companies such as Photobucket and Twitter. These gave him huge returns, and he has gone on to invest in businesses such as Uber, Instagram and cloud software company Twilio via his investment company, Lowercase Capital. Sacca is now worth $1.2 billion.

Troy Carter’s dramatic early life included his parents’ divorce when he was two, followed by his father’s imprisonment for murder. In 1990, aged 17, Carter dropped out of school to become a rapper. His group was signed to a label run by Will Smith and James Lassiter, and then he went to work for Jazzy Jeff. At age 23, he was promoting concerts for Notorious B.I.G., eventually becoming a music artist manager, and then co-founding the talent management company Erving Wonder in 1999.

By 2006, however, Carter was in debt, before being introduced to an emerging artist called Lady Gaga. Fortunes took an upturn, and Carter began several businesses, beginning with Coalition Media Group in 2007 and Atom Factory in 2010. In 2012 he created A-IDEA, a product development and branding agency, and AF Square, an angel fund and tech consultancy. This has invested in over 40 companies including Spotify, Songza, Dropbox, and Uber. Carter and Lady Gaga have since parted ways, but the guest Shark in the show's seventh season is reportedly still worth in the region of $60 million.

Bethenny Frankel’s early years were also fraught, with parents who fought and a mother who was, in Frankel’s words, “always drinking”. However, after school, Frankel found work as a production assistant on Saved By The Bell, before finding her way into TV as a contestant on The Apprentice: Martha Stewart in 2008. In that same year, Frankel was chosen for reality TV show The Real Housewives of New York City, which is when her career really began to bloom.

By 2010, Frankel had her own TV show but it was her book, Naturally Thin: Unleash Your SkinnyGirl and Free Yourself from a Lifetime of Dieting that was the catalyst to her biggest success. It helped to launch the Skinnygirl brand, which led to a cocktail company – later sold for $100 million – a luncheon meat product, an exercise DVD, and an audio book. Perhaps unsurprisingly, considering her extensive TV experience, Frankel was invited to be a guest Shark on seasons nine and 10 of Shark Tank. Her net worth has been estimated at around $25 million.

The world's richest self-made women

Known affectionately as the ‘Hollywood Brandfather’, Rohan Oza actually started on the manufacturing line as a Snickers bar box packer, but rose up to become the youngest manager to run the brand. That said, it wasn't an easy journey to the top, and he was fired from his first executive job as brand manager for Mars’ M&M's at just 20 years old.  After getting the boot, however, Oza went to work for Coca-Cola, where he was mentored and developed his skills.

Oza went on to work for brands such as Powerade and Sprite, before he became a partner in Glacéau. This brand’s products, such as Smartwater and Vitaminwater, were revitalized by Oza's branding prowess. Oza engaged celebrities such as Jennifer Aniston and Justin Timberlake to endorse the drinks, and Glacéau was bought by his former employer Coca-Cola in 2007 for $4.1 billion. Oza's net worth has been estimated at $200 million.

Kevin Harrington, like so many other Sharks, began work early, selling newspapers at the age of nine and launching his first business – sealing driveways – at 15. After this, he sold baby high chairs door to door, before launching his first multimillion-dollar business in the first year of college. But perhaps his biggest, and proudest, achievement is that in 1985 he invented the modern infomercial, after noticing that there was a lot of unused dead air time on television during the night. 

Since then, Harrington has launched many businesses, 20 of which have reached over $100 million in sales, and has created over 500 products. He is co-founder of both the Electronic Retailers Association (ERA) and the Entrepreneurs’ Organization (EO). He is also the founder of famous media company As Seen On TV. His ventures have produced over $5 billion in global sales. Harrington's wealth is reportedly in the region of $450 million.

Although he was born in war-torn Beirut, Marcus Lemonis had a grandfather who owned two Chevrolet dealerships in South Florida, and one of Lemonis’ early jobs was with one of these. When the business was acquired by AutoNation in 1997, Lemonis went to work for them in sales and management. Around this time, a family friend, Lee Iacocca, told Lemonis about his dream of "creating the largest RV (Recreational Vehicle) chain" in the US and asked him to help with this.

The pair set up Holiday RV Superstores, which ran from 2001 to 2003. Subsequently, Lemonis launched his own business, FreedomRoads. In 2006, this merged with Camping World, and with Good Sam Enterprises in 2011. Lemonis became CEO of Camping World. Other businesses include Marcus Lemonis Enterprises LLC, 1-800-Car-Cash, and AutoMatch USA. The star of CNBC's The Profit is now reportedly worth $900 million.

In her youth, Sara Blakely held some very diverse jobs, working for Walt Disney World, selling fax machines door to door, and even a stint as a stand-up comedian. She was successful at sales, however, becoming a national trainer at 25. However, she disliked the tights she had to wear for this role: Blakely hated the seamed toes poking from her open-toed shoes, but enjoyed the sleek look provided by the upper part of the underwear. Blakely began using her own money to experiment and, soon, Spanx was born.

Still aged just 27, Blakely had some trouble finding a manufacturer for her idea as most mill operators were used to dealing with established companies. Also, she soon discovered that most of the sector was run by men. Thankfully, one operator finally offered to help, after his three daughters encouraged him to do so. Now, Spanx is a successful global brand providing hosiery, leggings, and maternity wear. Blakely also co-owns basketball team Atlanta Hawks. The Shark Tank guest investor now has a net worth of a whopping $1.1 billion.

Matt Higgins is used to balancing several opportunities. After dropping out of high school aged 16 to take care of his sick mother, Higgins took night classes to gain his degree. Following this, he attended law school, again at night, while also becoming an award-winning investigative reporter by day, as well as working for the New York mayor as the youngest press secretary in history. Later, he co-founded, and became CEO of, RSE Ventures, a private investment firm specializing in sport, entertainment, media, marketing, food, lifestyle, and tech.

Through RSE, Higgins has helped build businesses such as restaurant software company RESY, the Drone Racing League, the International Champions Cup tournament, and leading brand strategy and communications agency Derris. Higgins is a stakeholder in many restaurants, including Momofuku, and has acquired a cybersecurity business, SkOUT Cybersecurity. This experience has made him the perfect choice as a guest inventor on Season 10 of Shark Tank in 2018. His net worth has been estimated in the region of $20 million.

The billion-dollar deal and other fascinating Shark Tank success stories