Or being part of the launch team at Skype. Or running The Accelerator Group and funding Last.fm.
Hang on. Maybe Klein is recognized most for being a partner at Index for eight years.
Well, you get the picture. He’s been instrumental in the rise of London’s digital economy for 20 years.
When he speaks, you listen.
And at Hot Topics’ London summit today, Klein did speak – with great wit and insight.
Here are a selection of his best moments.
“VCs should get more credit for long term thinking”
“Seed and VC investing is the longest term asset class. You’re looking at an eight to 12 year dividend.
“A hedge fund or private equity investor looks at three or four years. A high frequency trader – nanoseconds.
“It’s time VCs got some support for this.”
The UK’s advantage
“We speak English and we’re not American. Seriously.
“English is the global language of business and the internet. And though America has been great at commercialising technical innovation, we’re now living in world where America’s soft power doesn’t work quite as it did 40 years ago.
“I think that, and having access to capital talent and customers, gives the UK tech scene a real chance.
“London is the densest English speaking city in the world. If you’re not here, you’re nuts.”
“Asking London to compete with the Bay area and Beijing is not fair when you also expect it to compete with Dublin on taxes and Berlin on rent.
“It’s better to invest in Manchester and Leeds to get them to do that. It’s why I’m really excited that Jim O’Neill has been appointed to drive the growth of the North.”
The 20 year dividend of digital education
“The challenge of investing in education is that it’s an even longer investment than seed or venture.
“It’s a 20 year investment cycle.
“Today, the UK tech scene is still reaping rewards of the popularity of the BBC Micro, the Amiga and the Spectrum 40 years ago.
“I hope we can get the same impact from CodeAcademy and Kano and the recent changes to the UK schools curriculum.”
On life at Index
“People can be critical of Index. They see it as this family business because two brothers started it. They say ‘oh, it’s the Rimers’ business.’
“But I think that family component is great because it means people can argue, yet there’s a level of respect so that the next morning you’ll still get on. People still basically like each other.
Leaving Index after eight years
“Well, why did I leave home and go to uni? I could have stayed. My mum would have loved that!
“It was time. Before Index I was an entrepreneur that they backed. So I’m going back to work on the fund. It’s exactly the same as the old operation we’ve had for 16 years.
On hunting unicorns
“It’s incredible that the UK tech scene is now setting its sights at $1bn valuations.
‘When I was at LoveFilm, $100m was epic. Actually, $10m is pretty epic for most people.
“So beating ourselves up because we’re only the third biggest country producing billion dollar tech companies is a bit silly.
“It means we have great British ambition back. It’s only taken 150 years!”
The cost of talent
“People with talent should be able to command market rates. They shouldn’t be cheap if they’re solving important problems.
“I’ve run companies that have tried to cut costs by offshoring and so on, and it’s really hard to make it work.
“So pay the money. And if not, go and live in Cape Town or Portugal or Prague.
“Go to where the talent is, grow the business and then open an office in London or San Francisco.”