In August 2011, Tim Cook took the job as CEO of Apple, leaving many wondering if he could fill the shoes left by his friend and mentor, Steve Jobs. Business Insider reports on Thursday, Apple hit a huge milestone, becoming the first $1 trillion company in the United States , ever. That leaves Cook looking pretty good. But when he was first announced for the role, he was a big question mark. He had come out of seemingly nowhere to lead such a big, important company.