The idea for Super Mario Galaxy simply came from the game's producer, Shigeru Miyamoto, saying to the game's director, Yoshiaki Koizumi "Hey, can you make something with spherical worlds?" This idea became defined over a long period of time and would eventually turn into Super Mario Galaxy.

Miyamoto was known to provide vague comments and feedback that not many workers at Nintendo could completely understand and that only Koizumi was able to figure out the context for.