Kurt Geiger’s CEO went from cleaning toilets to running a $432 million fashion brand—he says he got promoted by making his boss look brilliant

Despite a less-than-glamorous start to his career after failing all of his school exams —and his early jobs including cleaning toilets and delivering paraffin—Kurt Geiger CEO Neil Clifford always knew his career was destined for greatness.

“I always had this sort of kryptonite glow in my stomach that I was going to make something of myself,” the boss of one of the world’s largest shoe retailers tells Fortune .

At the time, most people probably would have brushed Clifford off as a teenager with his head in the clouds. After all, he left school with just one qualification—in art—in 1983, joined the world of work at a Fiat car dealership, and cleaned bathrooms for extra pocket money.

Yet within a year he got his foot in the door of the fashion world as a sales assistant for Burton men’s wear, working for Ralph Halpern, the founder of Topshop.

"Suddenly, from not knowing what the hell to do with a terrible, embarrassing set of exam results, I'd proven to myself that maybe that wasn't going to ruin me—I was going to make it anyway," he adds.

Make it, he did: Less than a year later, Clifford was in charge of his own store in London. At just 19, he had to sack staffers who were stealing merchandise and lead the shop's turnaround. Then, over the course of 18 months, he saw promotion after promotion within the company until he was managing Burton's biggest store.

By 21, Clifford was the youngest store manager in the entire company.

Today, he’s running £330-million-a-year ($432 million) fashion giant Kurt Geiger—and has done so for more than two decades.

His secret to climbing the ranks so quickly? “You always have to make your boss look brilliant,” he says.

‘I’d rather step into their shoes than push them over the cliff’

Deep down, Clifford always wanted to be the big boss, and that mindset gave him drive even when he was at the bottom of his career journey.

“Whether it's cleaning toilets or cutting keys or delivering paraffin or selling oil filters or being a chief executive, I've always been very positive about work and not just because of money,” he continues. “I've always wanted to win.

“Even though I always made my boss look great, I sort of wanted them out of the way, really. I wanted to be in charge, always.”

The two statements may seem at odds at first. Why make your boss look good if it’s their job you want? In Clifford’s eyes, that's the best way of guaranteeing they’ll pull you up through the ranks with them.

“You don't want to be there chipping away at your boss negatively,” he explains. “You want them to be fabulous—you want them to love you and want to help you.

“I didn't want to get them fired. I want them to get promoted,” he adds. “I'd rather step into their shoes than push them over the cliff.”

Want to be a CEO? Be a team player first

It’s not just the boss that aspirational workers should be nice to. Numerous CEOs have repeated that it pays to be nice to everyone—including your competition.

Just like Clifford, Pret A Manger CEO Pano Christou dropped out of school and started his career at McDonald’s as a teen.

Now, Christou is CEO of one of Britain’s biggest sandwich chains. He cautioned that too many people often “ backstab ” their peers in their quest for a promotion—but it won’t help when you’re their boss.

“I won't stitch people up on my way up the ladder. And I think that has over time really reaped rewards,” he told Fortune.

It’s why, having being promoted into positions where he was often managing people far more experienced and older than himself, he said they “celebrated” his success—rather than envy it, or worse, sabotage his career.

Ultimately, it’s not just the affections of your future subordinates you'll win over in the process.

Even Amazon CEO Andy Jassy says that an “ embarrassing ” amount of your success in your twenties depends on your attitude—because managers would rather work with positive people.

“You pick up advocates and mentors much more quickly,” he said. “People want those people to succeed, and it’s very controllable.”

Plus, as Walmart CEO Doug McMillon highlights, how you behave at the bottom of the ranks can flag to managers the type of boss you’ll be.

McMillon began scaling the retail giant’s ranks by unloading trailers at 17 for $6.50 an hour to becoming the company’s youngest CEO since its founder Sam Walton. He cited being a team player as key to his success.

“Be a great teammate—you learn how to lead, you learn how to influence by the way you interact with your peers,” he said. “Treat them well, help them, help them do a better job.

“The next job doesn’t come if you don’t do the one you’ve got well,” the 57-year-old chief exec concluded.

This story was originally featured on Fortune.com