Cave Johnson

Cave Johnson is the founder of Aperture Science. Briefly mentioned in Portal he makes a more prominent appearance in Portal 2, in the form of tape recordings he leaves behind. His current status and whereabouts are unknown, presumed dead.

Shower curtains
In 1953 Cave Johnson sets up Aperture Fixtures, a shower curtain manufacturer. The precursor to Aperture Science, he chooses the name because it 'makes the curtains sound more hygienic'. He becomes a billionaire after winning contracts to manufacture the US Military's shower curtains.

Later life
Poisoned when he grinds up Moon rocks, which turn out to be poisonous, he falls gravely ill. Terminally ill and with little hope of a cure he instructs his engineers to start research on (AI) and  in the hopes his brain can be downloaded onto a computer. In the case he dies before the technology is realised, he leaves instructions that his secretary Caroline will take charge of Aperture Science (against her will). It is unknown what becomes of him.