Timothy Armoo became a multi-millionaire after selling his influencer marketing firm for an eight-figure sum when he was 27 years old, but he says that being extraordinary is no easy feat.

Armoo, the co-founder and former CEO of Fanbytes, grew up in a public housing development in an impoverished area of south London. He says that his remarkable success came with sacrifices like giving up on what he considered a healthy work-life balance.

"I believe in working extremely hard … I absolutely disagree with the idea of work-life balance," Armoo said in an interview with CNBC Make It.

"I think anyone who has achieved anything of significance has not done it by being balanced. It's just a myth."

Armoo explained that "there is a season for everything," which he said were time periods when you have to work extremely hard. He said these periods might look different for different people and they could be three months, three years or even 10 years in length.

"There is a season where you say, 'I want to achieve this goal and I want to get different results to other people. I want to get extraordinary results.' The way you achieve those extraordinary results is by doing extraordinary things, which literally means doing things that are not ordinary," he said.

This means instead of being balanced, you put in extra effort which "increase your odds of success."

'Seasons'

Armoo reiterated his point on having "seasons," saying this could mean leaning into work when it's time to hustle — and then prioritizing family, health, and personal life during other seasons.

"You should also not have work-life balance when you're in your family season. You should just be so intensely focused about creating the best family that you can," he said.

Armoo was only 14 years old when he started his first business, a tutoring company where he connected students who needed help with other students who were good at a particular subject. He took a cut of the fee.

By the age of 17, he had sold his second company, an online blog called Entrepreneur Express, for £110,000 (around $145,000.)

He follows in the footsteps of many CEOs and billionaires like Bill Gates, and Warren Buffett who have all dedicated large portions of their life to building their companies.

Gates, the co-founder of Microsoft, recently told CNBC Make It that he didn't believe in taking vacations and weekends in his 20s, but that now as a 68 year old he advises people around him to take a break when they can.

Meanwhile, 94-year-old Buffett, the chairman and CEO of Berkshire Hathaway, still works six days a week and goes to the office on Saturdays.