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
Where Hospitality Ends, Security Begins.
For decades, Conrad’s Ruth Villa ran on relationships, not rules. As the Middle River venue grew to 20,000+ guests a year, owner David Conrad knew it was time for specialized expertise. Here’s how Defender One built security guidelines that protect guests and preserve the hospitality they love.
What’s In Your Security Report? (And Why It Matters More Than You Think)
Most organizations check the box the moment a guard is posted at the door. But a body in a uniform isn’t a security program — a real program is something you can see. Here’s what a security report should actually tell you, and what it means if you’ve never gotten one…
Security That Knows Your Facility’s Culture
The JCC of Greater Baltimore’s events-driven campus needs guards who know the community, not just the building. Read the case study to see how Defender One’s consistent armed and unarmed coverage, hospitality-minded approach, and law enforcement experience support staff, members, and families every day.
Management Makes A Difference
With 24/7 coverage across high-traffic properties like Metro Centre at Owings Mills, David S. Brown can’t afford inconsistent security. Read the case study to see how Defender One’s locally owned leadership, low guard turnover, and hands-on ownership deliver the reliability and fast response a busy commercial portfolio demands.
Preparing for the High Holidays: A Security Checklist for Your Congregation
High Holiday Preparedness Rosh Hashanah and Yom Kippur bring some of the fullest sanctuaries of the year. Parking lots fill up faster. Guest lists grow. Services run longer, and routines that work fine on a quiet Saturday get tested in ways they don't the rest of the...
Is Your Security Guard Asleep on the Job? Here’s What It Really Means
Your Guard Was Sleeping. Why Haven't You Changed Providers? It happens more than the security industry likes to admit. A manager walks the floor, checks a monitor, or steps outside — and finds their security guard asleep on post. Maybe it's happened to you. Maybe it...