Trusted Security Guard Services for Maryland, D.C., and Pennsylvania
Family-owned and led by a seasoned law enforcement professional, Defender One delivers reliable, responsive contracted security guards tailored to your needs.
We Care About Your Safety
Defender One Security delivers trusted, comprehensive security solutions across Maryland, Washington, D.C., and Pennsylvania. Founded in 2009 by Baltimore native Jon Krieger, the company remains proudly family-owned and operated.
With more than 30 years in law enforcement—including leadership roles in patrol, internal affairs, traffic, and community outreach—Jon launched Defender One to bridge the gap between private security and public safety. That same commitment to professionalism, accountability, and community still drives the company today.
As a family-run business, Defender One offers a level of personal service and responsiveness national firms often can’t match. Jon and his wife Jennifer oversee daily operations, working directly with clients to ensure every detail is handled with care and integrity.
Trusted Security Solutions Since 2009
Decades of experience, grounded in law enforcement leadership and a commitment to professionalism you can count on.
Highly Trained Security Guards
Our team is made up of skilled, vetted security guards trained to deliver preventative, site-specific protection.
24/7 Coverage and Peace of Mind
We provide around-the-clock security through contracted services—ensuring consistent presence, not reactive response.
Family-Owned, Personally Committed
We’re not a faceless franchise. Every client matters, and every detail is handled with care by our leadership team.
Don’t leave safety to chance. Work with a team that treats it like a priority—because it is.
Our Comprehensive Security Services
Reliable Security Presence for Your Property
Uniformed security professionals stationed at your facility to deter threats, safeguard property, and ensure a safe environment. Ideal for corporate offices, retail, schools, healthcare facilities, and more.
Executive and Personal Security You Can Trust
Whether you need discreet protection for an event or long-term security for high-profile individuals, our team delivers peace of mind with professionalism and discretion. Transportation services available.
Fast, Professional Fingerprinting for Individuals & Teams
Efficient fingerprinting for employment, licensing, compliance, and more. Available for individuals or coordinated group sessions. Walk-ins accepted Monday-Friday9:30 AM – 4:30 PM.
From Our Clients
Defender One is an incredible company to work with. Their security team is professional and pleasant to work with. I have seen members of their team deal with a variety of emergencies and all were handled efficiently and had great outcomes. I feel completely safe working with Defender One and I am so thankful they are here to protect us.
Provides excellent, expert services for our organization.
We love Defender One! They always do an excellent and professional job for our organization! Thank you once again for keeping our community and members safe.
It was a pleasure using Defender One for our security needs. They were very professional and punctual. I highly recommend Defender One for ALL your security needs
News & Resources
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School safety goes beyond academics; it’s about preparing students to handle anything that comes their way. Emergency drills equip elementary schools with preparedness strategies, helping students and staff respond confidently to the unexpected. By familiarizing young...
Creating a Safe School Culture Starts With Our Community
Creating a safe school culture starts with our community fostering trust, open communication, and active involvement for lasting security. When communities support school safety together, they establish an environment where students thrive, feel secure, and grow into...
What to Do When a Security Threat Disrupts Worship Services
Houses of worship are places of peace, reflection, and community. Yet, in recent years, security threats have affected many such spaces, bringing the safety of congregants and staff into sharp focus. Knowing what to do when a security threat disrupts worship services...
Partnering with Communities for Better Security Awareness
Security challenges in hospitals and corporations require a proactive approach to be effective. By partnering with communities for better security awareness, healthcare, and corporate organizations can build safer, more alert environments through shared efforts. These...