Jeffrey Castellanos: Building Trust Through Experience, Relationships, and Real-World Expertise

For commercial generator customers throughout Long Beach and the South Bay, reliability matters. They need partners who understand their facilities, their operational challenges, and the importance of keeping critical power systems ready when they’re needed most.

That’s exactly what Sales Engineer Jeffrey Castellanos brings to every customer relationship.

Jeff’s journey at Duthie Power is a testament to hard work, continuous learning, and a genuine passion for helping people. Having worked his way through multiple roles within the company, he offers customers a unique combination of technical knowledge, field experience, and relationship-driven service that can only come from learning the business from the ground up.

From the Parts Department to Sales Engineer

Jeff’s career at Duthie didn’t begin in sales.

“My path to becoming a Sales Engineer didn’t begin with an engineering degree or years of technical training—it started with family, culture, and a relentless work ethic instilled in me by my immigrant parents.”

When he first entered the generator industry, he started in the Parts Department, where he learned the business one component at a time.

“I didn’t know much about generators when I started,” Jeff says. “I learned piece by piece, bolt by bolt.”

Driven by curiosity and a desire to grow, he immersed himself in every opportunity to learn. He worked closely with experienced team members Everardo and Jairo, asking questions and gaining a deeper understanding of generator systems and support operations. He also connected with Duthie’s Service Manager and regularly requested ride-alongs with technicians to see firsthand how equipment was serviced and maintained in the field.

That hands-on experience gave Jeff an understanding of customer challenges that many sales professionals never have the opportunity to develop.

As his knowledge grew, he moved into a quote follow-up role, helping customers navigate service recommendations and approvals for projects under $5,000. Working closely with technicians and customers alike, he learned how to interpret technical recommendations, communicate solutions clearly, and ensure customers had the information they needed to make confident decisions.

From there, Jeff advanced into account management, overseeing major customer portfolios with more than ten locations. Today, as a Sales Engineer serving Long Beach and the South Bay, he brings together years of experience across parts, service, account management, and sales to help customers develop reliable power solutions.

A Foundation Built on Family and Hard Work

Much of Jeff’s success can be traced back to the values instilled in him by his family.

“Growing up in a Spanish-speaking household, I learned two powerful values early on: el valor del trabajo duro (the value of hard work) and la importancia de la familia (the importance of family),” he says, “These principles have shaped every chapter of my journey.”

Those lessons continue to guide how he approaches both customers and colleagues. They inspired him to start at the bottom, remain humble throughout his career, and treat every colleague and customer with respect and authenticity.

At Duthie, those values align closely with the company culture that Jeff says has played a major role in his professional growth.

“The family-oriented culture here is one of the biggest reasons I’ve stayed,” he says. “People genuinely care about each other.”

Connecting with Customers Through Trust and Communication

While Jeff’s technical expertise is a significant asset, what truly sets him apart is his ability to connect with people.

A self-described extrovert, he loves being in the field, meeting new customers, and building relationships. In fact, one of his favorite parts of the job is making cold calls and introducing businesses to the services Duthie provides.

For Jeff, every conversation is an opportunity to understand a customer’s needs and build trust.

His bilingual Spanish-English communication skills have also become a valuable advantage for many customers throughout Southern California. Over the years, Jeff has found that speaking Spanish often helps create connections that might otherwise never happen.

Whether he’s introducing himself at a facility with limited access, speaking with maintenance personnel, or building relationships with Spanish-speaking stakeholders, Jeff understands that trust starts with communication.

“In those moments, Spanish becomes more than a language,” he says. “It’s a bridge.”

Those connections often lead to stronger customer relationships and more effective communication throughout a project’s lifecycle.

Delivering Results for Critical Facilities

One of Jeff’s proudest professional accomplishments has been helping secure preventive maintenance services for the Port of Long Beach, one of the region’s most important and recognizable organizations.

The achievement reflects his ability to combine persistence, relationship-building, and technical knowledge to earn the trust of large commercial customers responsible for critical operations.

For facility managers, property owners, and operations teams, Jeff’s background provides a significant advantage. Having worked alongside technicians, managed customer accounts, and supported service operations, he understands both the technical requirements of backup power systems and the business realities customers face every day.

His goal is not simply to sell services. It’s to help customers maintain reliable systems, reduce risk, and protect their operations.

A Passion for Adventure and Growth

Outside of work, Jeff brings the same energy and curiosity to his personal life that he brings to his career.

He enjoys traveling, exploring new cultures, and spending time with his wife and two sons. During the winter months, you’ll often find him snowboarding with his family, creating memories on the mountain and embracing his love of the outdoors.

His adventures have taken him around the world, from Guatemala and Costa Rica to backpacking throughout Europe after high school. He’s also an enthusiastic food lover whose family enjoys discovering new cuisines and experiences together.

That passion for exploration reflects the mindset that has guided his professional journey.

“There’s always something new to learn,” Jeff says.

It’s a philosophy that aligns perfectly with a Duthie principle he still carries with him today: Learn. Grow. Evolve.

From pulling filters in the Parts Department to helping commercial customers navigate complex power challenges, Jeff’s career is proof that expertise is built through curiosity, persistence, and a commitment to continuous improvement.

For businesses throughout Long Beach and the South Bay, Jeffrey Castellanos is more than a Sales Engineer. He’s a trusted advisor who understands generators from the inside out, values relationships as much as results, and is committed to helping customers keep their critical operations powered and protected.