Back in the 1990s, Leach was a teenager trying to save enough money to pay his way through community college in California. His high school sweetheart had just wrapped up a summer internship at MiniMed, an insulin pump company, and before heading back to school, she offered Leach the chance to take over her job.

It wasn’t exactly glamorous work cleaning lab equipment like beakers and flasks, but it would mark the start of an entire career focused in diabetes management. Nearly three decades later, Leach is now the CEO of Dexcom, a roughly $30 billion company that develops non-invasive glucose-monitoring systems.

And while he never had grand plans to be a healthcare executive, he told Fortune that his climb up the career ladder has come down to one simple recipe: 

“It’s all about hard work,” Leach said. “There’s no shortcut.”

How his grandfather and a childhood love of engineering shaped the career of Dexcom’s CEO

Leach grew up in California’s San Fernando Valley, where his father worked in groundskeeping at a Catholic school and his mother was later a teacher’s aide. Money was tight, but he learned early that if he wanted something, he would have to find a way to earn it himself.

In elementary school, for example, he desperately wanted a $350 bike—an expensive purchase for his family at the time. When he learned about layaway, he decided he could save up for it himself.

“With the income of my family, I had no business having that kind of a bike, but I just wanted it so bad,” Leach said.

He spent the summer washing cars for $2 apiece, slowly putting money aside until he could afford it. The experience taught him something that would follow him throughout his career.

“Hard work gets you what you want, and you know you may not always succeed, but you can control it—you can control that outcome,” Leach said.

He also developed an early fascination with how things worked, thanks in part to his maternal grandfather. A handyman who could tackle everything from plumbing to electrical work, he often brought Leach along to work on projects around the house. By the time he was 10, Leach was learning how light switches worked, how to wire them, and how electrical panels operated.

Those afternoons helped spark an interest in electrical systems that eventually extended to experimenting with old VCRs and building homemade rockets.

His grandfather would also become part of the reason Leach’s eventual career in diabetes technology carried a personal connection. After his grandfather’s gallbladder abruptly ruptured, the family learned the medical emergency was related to his diabetes. He would go on to take insulin for the rest of his life.

Leach didn’t yet know it, but those experiences would help shape both his engineering interests and his eventual career.

He eventually took classes at Glendale Community College before transferring to UCLA, where he studied electrical and biomedical engineering and became the first person in his family to earn a four-year college degree.

That $10-an-hour job washing beakers and flasks at MiniMed eventually turned into a full-time position, too. Leach spent seven years at the company, which was acquired by Medtronic in 2001. But in 2004, he received an offer to join a startup of 30 people called Dexcom, which was looking to challenge the established diabetes technology industry.  

The opportunity offered something different: a chance to help build a company from the ground up—and double his salary from $45,000 to $95,000.

Dexcom’s CEO never asked for a promotion in his life—but tells Gen Z to get ‘outside your swim lane’

Now more than two decades after joining Dexcom, 48-year-old Leach has watched the company grow into a healthcare giant. The company went public in 2005 and, by 2025, brought in $4.6 billion in annual revenue, had approximately 3.5 million users globally, and had around 11,000 full-time employees worldwide.

The company has benefited from a shifting diabetes-treatment landscape, including the growing popularity of GLP-1 drugs, which are used to treat type 2 diabetes and have helped bring greater attention to glucose monitoring.

In January, Leach reached the top of the organization as president and CEO. His compensation now includes an annual base salary of $1.15 million—a far cry from the $10 an hour when he first was exposed to the industry

But his ascent wasn’t driven by an elaborate career plan. Leach, who became Dexcom’s chief technology officer in 2018 and chief operating officer in 2022, said he rarely thought about what position he wanted next.

“It’s always been: keep doing a really good job, keep solving big problems, keep fostering leaders, teaching people, [and] learning from other people,” he said.

Throughout his 22-year career at Dexcom, Leach said he never once asked for a promotion. Instead, he focused on proving himself in the roles he already held, allowing his work to speak for itself.

Additionally, Leach made a habit of being the teammate willing to volunteer for the less glamorous assignments his colleagues weren’t particularly eager to take on.

“A lot of times we tend to focus on our own work and what we’re trying to get done, and it’s really helpful sometimes to take a step back and say what’s right for the company, not necessarily what’s right for me or what’s right for the function I’m leading,” Leach said.

For young workers hoping to distinguish themselves early in their careers, that willingness to look beyond their immediate responsibilities can be a major advantage, he added.

“It’s like getting outside your swim lane,” Leach said. “Everyone kind of has their functional swim lane. You got to get out of that, and I think that’s when you become a more valuable leader for an organization.”