Yuzo Kano is trying to build a global cryptocurrency powerhouse, one former financier at a time.

The Goldman Sachs Group Inc. alumnus, who turned bitFlyer Inc. into Japan's largest bitcoin exchange, is scooping up traders and bankers from both his old employer and former rivals as he embarks on an ambitious international expansion.

Kano's team, which includes a former fixed-income desk head at Barclays PLC and an ex-senior private banker at Credit Suisse Group AG, has doubled to more than 150 people in the past six months and is on pace to top 300 before year-end.