More specifically, Steve Jobs founded NeXT after Apple pushed him out in the late 80s.
A decade or so later, Apple was on the tail end of a long, slow, downward slide. The team wasn't happy with the current state of their Mac operating system, and bought out NeXT to use their software as the basis of its replacement (Mac OS X).
Jobs, as CEO of NeXT, came back to Apple as a consultant, but was CEO again in a matter of years.
