Takahiro Kusakari went from being a self-described bum getting by on bit-part acting roles in Tokyo to calling the shots at a $2.7 billion stock fund.

His life changed in 2007 when the then 28-year-old stumbled into a seminar by the legendary investor Atsuto Sawakami, the founder of Japan's biggest independent mutual fund. Sawakami saw a spark and later offered him a job. What followed was a meteoric ascent from back-office lackey to analyst, then fund manager and finally chief investment officer.

As it turns out, Kusakari's lack of experience probably worked in his favor. His mentor has preached the gospel of long-term investing for more than four decades and says most people in finance don't really get what the term means, so it made sense to turn to someone from outside the industry.