Nidec Corp. founder Shigenobu Nagamori is back at the helm as chief executive officer of the motor maker again at the sprightly age of 77.

A workaholic, notoriously dismissive of what he sees as slacking-off younger generations, Nagamori can’t seem to stay away from the company he founded with three friends in a shed, overseeing its rise from a maker of tape recorder parts to the leading producer of motors for hard disks. It is now expanding supplying parts for electric cars.

After luring Jun Seki from Nissan Motor Co. and installing him as successor last year, Nagamori swiftly demoted him with shares down 40% since hitting a high last year. "At a time like this, I will take command in the short-term to improve performance,” Nagamori said on April 21, "as the founder and the person who knows everything.” What would the company do without him?