The teenage years aren’t always the smoothest, and life was no different for four of the world’s most successful chief executives.

They may be heavy hitters now, but before they made it, they included an awkward adolescent, a teen factory worker, a “terrible” student and a 16-year-old who held three jobs.

Bill McDermott, now CEO of software giant SAP, loved the scent of success as an adolescent. Having the gumption to buy a business is impressive at any age, but McDermott snapped up his neighborhood delicatessen for $5,500 — at the age of 16.

It wasn’t bankrolled by his mom and dad: He’d been working since the age of 11, and by the time he bought the Amityville Country Delicatessen, Long Island, he also was running a paper route and waiting tables.

“I was actually simplifying my life. I had three part-time jobs. One of them, of course, at that time was the deli itself,” he told CNBC’s TV show “The Brave Ones.” “So I had a little bit of an inside scoop on how to work the deli. But how I did it was simple. The owner of the business wanted out, so there was a good motivation. And he was willing to trust me, because no one else wanted to buy it.”