David Westerberg, an accomplished dentist from California, scanned the field of officers standing outside the Navy Officer Development School in Newport, Rhode Island. He was looking for his son. What he found was a second calling.
Jacob, his son, was an organizational psychologist with a PhD, and today he was graduating the 5-week ODS program alongside other professionals who found themselves in high demand in the Navy, such as physicians and lawyers. But two of Jacob’s classmates grabbed his dad’s attention.
“I noticed two gentlemen with gray hair and asked my son who they were,” said Westerberg, who is currently a lieutenant commander. “He said they were reservists — one was a surgeon and the other a dentist. They were both in their 60s. That got me thinking.”
That parade field discussion led Westerberg to a deep dive on Google and a call to Jacob’s recruiter.
“Is there a place for a 64-year-old dentist?” Westerberg remembers asking. “I just kept moving forward with the paperwork, telling myself I’d continue until someone told me I couldn’t go any further.”
Within a year, Westerberg found himself on that same Rhode Island graduation field in 2022, a newly commissioned Navy dental officer at 64. It hadn’t come easy. He’d woken an hour earlier than his ODS classmates to stretch before their early morning runs, but a few weeks in and he was hanging with sailors in their 20s and 30s.
“I had no idea this was even possible,” said Westerberg.
Determined to experience all the Armed Forces had to offer, he secured a greenside billet, meaning he’d be training alongside Marines. He’d learned of the Fleet Marine Force qualification, a designation that demanded strong knowledge of all things Marine Corps, including their history, weaponry and aircraft, and logistics. It was a challenge, an experience that Westerberg wasn’t going to pass up.
As part of the process, Westerberg completed a qualification book bearing signatures that verified he’d mastered everything from qualifying with a pistol to understanding the mechanics of a seven-ton truck. Soon after came a written test – “a couple hundred questions” – followed by fielding questions from Marine officers during a 3-hour oral board.
“For the last three months before the board, I became completely hyper-focused. I studied every morning and hours on the weekends,” said Westerberg, who went so far as to slip in study time between patients at his private dental practice.
In June 2026, he became the oldest sailor to earn the Fleet Marine Force Insignia, pinning the gold and silver device to his uniform at 67.
“I had no idea I was going to become the oldest person ever to earn this,” he said. “My goal when I joined the Navy was simply to experience as much as I could. I knew I had a short window because I’ll age out at 68.”
Westerberg began his service knowing he’d be out in four years, but he remains intent on squeezing as much life experience and meaning as possible out of these last several months. On drill weekends, he travels to join other dentists in conducting pre-deployment care on young Marines.
“They’re anxious, excited, and ready to deploy,” he said. “Being able to play even a small role in helping them get ready gives me tremendous purpose.”
And his service has built a unique, deep bond with Jacob, his active-duty son, who unknowingly laid the path for his father to serve when most consider retirement.
“It’s been a lot of fun for both of us,” he said. “If I hadn’t gone through this myself, I never would have fully understood what he does.”
Now, as mandatory retirement approaches, Westerberg said his service is the most meaningful chapter of his professional life.
“I feel incredibly fortunate to have experienced this at this stage of my life,” he said. “I still can’t believe I’m doing it.”
