Paul English: Building Kayak, bipolar disorder, and the immigrant mindset

Executive overview

Paul English co-founded Kayak, sold it to Priceline for $1.8 billion, and walked away with $120 million — while managing bipolar disorder for 30 years. His story shows that a founder's psychology, including its darkest parts, is inseparable from how they build.

Kayak ran a referral model — charging $0.75 per flight and $2 per hotel lead — achieving $1.5M revenue per employee, one of the highest ratios among all public companies. Paul learned to negotiate from watching his father at yard sales, left $1M in vested options on the table to chase a startup, and gave half his exit proceeds to his team.

Success doesn't require a clean psychology — it requires channelling what you have.

Early pattern: obsession, self-direction, and the first business

• At 12, Paul ran a drug distribution business from his attic, netting enough profit to have bought several used cars
• Refused to do homework but was intensely industrious outside school — he chose what he mastered
• Taught himself to code in his school's basement computer club; felt the first moment of genuine control
• Discovered programming offered a world where he was always in charge — a "refuge inside a refuge"
• Found a bug in his brother's published Frogger game (4 million copies shipped) that no one else had found

The Kayak business model

• Kayak was a travel search engine, not a booking engine — it sent users to airlines, hotels, and OTAs
• Revenue per referral: $0.75 for flights, $2 for hotels, more for completed bookings
• 1.2 billion searches in 2012 generated $292M revenue and $65.8M profit
• Only 205 employees — revenue per employee approached $1.5M, one of the highest among public companies
• A real-time search counter on the office wall displayed live daily searches, keeping engineers connected to commercial impact

Bipolar disorder: how it manifested and what it cost

• Diagnosed with bipolar disorder in his late twenties; initial diagnosis came after months of volatile coding and outbursts in meetings
• Suffered near-immobilising depression, including after the Kayak sale announcement — peak success triggered his lowest point
• Hypomania produced physical sensations: tingling limbs, racing blood, colour shifts, hyper-alertness — he described it as "blood racing through my veins"
• In high states: grandiosity, impulsivity, giving away large sums of money, alcohol use to self-regulate, sleeping with people he later regretted
• Cycled through a dozen medications over decades; repeatedly quit lithium because it flattened his energy — he couldn't tolerate losing "the fire"
• His own summary: "It feels so good that when it is with us, we feel cured, perfect, and we don't want the meds anymore"

How he built and led teams

• Kept a core group of lieutenants across multiple companies over two decades — when one venture ended, he'd reassemble them for the next
• Ensured his two key lieutenants held Kayak stock worth ~$20M each at exit
• Gave half of his own Boston Light Software proceeds ($~4M of $8M) to his team
• Enforced small meetings: kept a tally-clicker outside the main conference room; target was three people, not ten
• Became disengaged post-acquisition — within weeks of the Priceline deal closing, he was working three hours a week and didn't know the names of new staff

The negotiation: yard sales to $33.5M

• Paul's father bought broken air conditioners at yard sales, repaired them, and sold them in summer — his tactic was to open with a ridiculous lowball to unsettle the seller
• Paul absorbed this as a child and applied it directly when selling Boston Light Software
• On advice from a colleague, he opened negotiations with Intuit at $40M for a six-month-old company with 15 employees and $50K in revenue
• The Intuit negotiator hung up; he called back, acknowledged the number was crazy, and claimed he was talking to four other buyers
• Final price: $33.5M
• When he told his father the number, his father asked "Who negotiated for you?" — Paul said he had, using exactly what he'd watched his dad do at yard sales

The compounding logic of failure and persistence

• Net Centric (internet fax startup) failed; Paul left Interleaf to join it, abandoning $1M in unvested options
• After Net Centric collapsed, Paul spent three years in depression, doing freelance programming at $80/hour
• Built a Shogi forum that Yahoo! offered to acquire — declined because it required relocating to California
• Founded Boston Light Software in 1998 (a website builder) and sold it to Intuit in 1999 for $33.5M; kept $4M after giving half away
• Founded Kayak in 2004; sold for $1.8B in 2012
• The pattern: one or two hits pay for a lifetime of failures — batting average is the wrong metric

The democratising logic of technology

• Tom, Paul's older mentor, observed that Boston's Anglo-Saxon elite had gatekept opportunity for decades — but technology created an exception: ability mattered more than accent or family name
• Knuth's claim: only ~2% of people are born to program computers, due to specific "psychological oddities" — Paul fit that profile
• Naval Ravikant's parallel observation: the internet has massively expanded the possible space of careers, and most people haven't caught up to that yet
• Paul embodied the "new American" ethos: you don't have to do what your father did, or what you were doing six months ago — only invention matters

On money and guilt

• Grew up one of seven kids in a family where no one was supposed to be special
• Strong "communist streak" alongside his capitalist output — discomfort with wealth accumulation
• Befriended an older Boston construction magnate who built a multi-hundred-million-dollar company and spent his final decades trying to die broke, donating to Haiti and other causes
• Paul gave away significant sums during hypomanic highs; gave half his Boston Light proceeds to his team unprompted