Klarna Founder: From $0 to $46 Billion: Sebastian Siemiatkowski | E98

Sebastian grew up as a Polish immigrant in Sweden, financially poorer than his peers and seen as ‘different’ in name, religion, and background. Watching educated parents unable to realize their potential felt deeply unfair and created an emotional drive to “fix it” through achievement. He links this to data showing a high share of Silicon Valley founders are immigrants, and argues societies should actively channel immigrant frustration into constructive paths—sport, music, entrepreneurship—otherwise it risks turning into destructive behaviors like riots or crime.

As a child, Sebastian was academically ahead and became disruptive out of boredom in a system that treated everyone the same. He now deliberately designs Klarna as a ‘Champions League’ environment: explicitly not for everyone, but for people who want to be pushed, learn fast, and make a big impact. He compares the ideal manager to a great swimming teacher or personal trainer who can push each person just to the point of fear and progress, without breaking them—a fine-grained, individual calibration that’s hard to scale but essential for growth cultures.

Early in Klarna, Sebastian and his co-founders relied heavily on older corporate executives and advisors who had never actually built high-growth tech companies. Their advice on engineering speed, structure, and culture was often wrong but sounded authoritative. Sebastian now distinguishes between people who *built* success and those who merely *worked at* successful companies, and warns founders to be extremely selective and skeptical: “Be careful with who you're listening to. Have they really contributed to success?”

Sebastian co-founded a large fintech despite not being able to code. This created huge early challenges: they gave 37% of Klarna away to external engineers due to a misunderstanding, then struggled to judge CTO performance and engineering quality. He closed the gap by (1) sitting next to his CTO and watching him debug and write tests to build intuition about effort and complexity; (2) meeting multiple external CTOs with his own to compare philosophies, answers, and optimism; and (3) steadily upgrading technical leadership when it was clear the existing CTO wasn’t right for building a global-scale tech company.

On issues like work-from-home or agile methods, Sebastian resists top-down, one-size-fits-all mandates. He’s seen how overly prescriptive rules let middle managers abdicate responsibility (“because management said so”) and stifle learning. Instead, he wants a small set of non-negotiable ‘team rules’ (like a football team always training) and above that, a culture where managers must justify choices to their teams, experiment, and adapt. He highlights Toyota’s practice of making managers stand in a circle on the factory floor and *observe* until they can articulate real insights—learning by doing, not by decree.