Richard Ketchum, chief executive officer of the Financial Industry Regulatory Authority (FINRA). (Andrew Harrer/BLOOMBERG)

Everyone has to start somewhere. And somewhere usually is an underwhelming first job. This piece kicks off a series on the first jobs that top executives today held and the surprising lessons they took from those experiences.

Richard Ketchum started out with sweaty summers mowing down miles of golf course grass. Today, he serves as chairman and CEO of the Financial Industry Regulatory Authority (FINRA), the largest independent securities regulator in the United States.

In some ways, clocking in at 5 a.m. each morning at New York’s Schenectady Municipal City Golf Course was good practice for the market hours he has to monitor today. Before golfers arrived, Ketchum manicured the greens with other college kids who were home for the summer.

“There was nothing like summer jobs back then to remind you why college wasn’t that bad,” he says of having to wake up at those early hours when you only see milkmen stirring on the street. “It didn’t keep us entirely out of the bars, but I and my friends at the golf course would just be leaving when everybody else was coming in.”

Between maintenance tasks on the course, there was a lot of downtime. Sometimes he and his co-workers would escape to nap at tucked-away spots like sheds and gazebos.

Not that he always got away with his siestas.

Ketchum remembers how his then middle-age boss, greenskeeper Bill Waltman, would drive around the golf course to find sleepy summer employees — and then deliver a lecture on taking pride in what you do.

“You could never fool him,” Ketchum says. “He was remarkable in his maturity and his continuing positive views. And the job was obviously not his life dream.”

Ketchum recalls how Waltman mentored the college and high-school kids who worked on the course, and taught them how the commitment and care you put into a job matters. Ketchum also took a life lesson from Waltman’s deputy, a high-school graduate in his mid-20s who had taken on the job to support the two kids he had with his girlfriend by accident.

Ketchum says that a “lesson I learned was how easily [stuff] happens and how important it was to get that college degree.” He also learned to respect those who didn’t. “They are often as talented and as insightful and certainly as caring as you. That kind of lesson on how you treat people has been important to me all my life.”

Fast forward from Ketchum’s own early days working at the golf course, and he’s now seen his three kids go through a series of their own far-from-ideal first jobs.

“Your skills are not really recognized, but the importance of caring about what you do and delivering, even if it’s beneath your skill set, is huge.”

Ketchum has remained close with his co-workers from the golf course — one was even the best man at his wedding. But they don’t spend time on any greens together anymore. They refused to play golf after their summers tending the Schenectady greens.

Well, all of them except Ketchum.

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On Leadership: @post_lead | Reporter: @echristinalee | Editor: @lily_cunningham