Inside ThreatLocker’s Rise from Startup to Global Cybersecurity Company

From Startup to Global Cybersecurity Company, ThreatLocker

Cybersecurity company ThreatLocker has grown from a small startup into a global technology firm employing more than 700 people.

Founded by entrepreneurs Danny Jenkins and Sami Jenkins, the company built its platform around a strict deny-by-default security model commonly described as Zero Trust. Instead of trying to detect cyber threats after they appear, the system blocks unauthorised software from running in the first place.

Speaking at the company’s sixth Zero Trust World conference in Orlando, ThreatLocker’s leadership outlined how this approach has driven the company’s rapid growth and international expansion.

Danny Jenkins says the philosophy behind the platform is intentionally simple.

“We just figure out what needs to run on a system and allow that to run perfectly,” he said. “Everything else is irrelevant. It doesn’t need to be there.”

This principle, allowing only what is explicitly approved to run, sits at the core of the company’s platform.

A Different Approach to Cybersecurity

Traditional cybersecurity tools attempt to detect malicious behaviour or known threats. ThreatLocker takes a different approach by blocking everything by default and allowing only approved applications to run.

The aim is to prevent ransomware and other attacks before they can execute.

Jenkins believes the cybersecurity industry sometimes overcomplicates the problem.

“Everyone wants to think there’s some kind of magic formula,” he said. “But it’s simple. You create a really good product that solves a real problem and then you make sure people understand what it does.”

Seamus Lennon, Vice President of Operations for EMEA at ThreatLocker, says the model reverses how many traditional security systems operate.

“For the past twenty years security tools have tried to stay one step ahead of attackers,” he said. “With a deny-by-default model you allow only what is required and block everything else.”

From IT Services to Cybersecurity Platform

The idea behind ThreatLocker emerged from the founders’ earlier work running IT services and security businesses.

While managing IT systems for customers during the 2010s, Danny and Sami Jenkins repeatedly saw ransomware and malware bypass existing security tools.

Sami Jenkins said the product grew directly from that experience.

“We were running IT management services and kept seeing the same issue,” she said. “We looked for products that could solve it but couldn’t find anything that worked the way we needed. So the only solution was to build one.”

Development began in 2015 and the first version of the platform was released in 2017.

In the early stages the company consisted of only a handful of people working on the product. Today it has grown into a global cybersecurity company employing more than 700 staff.

Sami remembers the financial risk involved in building the business.

“We basically went bankrupt building this company,” she said. “Credit cards and everything went into it. So it’s very rewarding now to see the impact it has.”

Irish Roots in the Company’s Story

Ireland also played an early role in the story of ThreatLocker.

Sami Jenkins, whose maiden name is Samantha Yorke, grew up in County Meath close to the border with County Cavan. She met Danny Jenkins while he was working in the nearby town of Kingscourt, and the two entrepreneurs went on to build several technology businesses together.

“We met in Kingscourt,” she said, and their partnership developed from there.

Before founding ThreatLocker, the pair established and later sold two earlier technology businesses, including ventures in email security and IT management services. Their work supporting IT systems for customers ultimately led to the development of the ThreatLocker platform.

Why Organisations Adopt the Platform

ThreatLocker’s customers include large enterprises, managed service providers and organisations in sectors such as finance, manufacturing and healthcare.

Many organisations deploy multiple cybersecurity tools but use only a fraction of their capabilities.

Seamus Lennon, Vice President of Operations for EMEA at ThreatLocker, says the company’s deployment model helps organisations get more value from their technology investments.

“One of the biggest problems in IT is that companies buy products but only use a small percentage of their capabilities,” he said. “If our solution engineers do their job properly, the end user shouldn’t even realise ThreatLocker is there.”

The system is designed to strengthen security while reducing the complexity of managing multiple tools.

Enterprise Customers and MSP Partners

ThreatLocker’s platform is used directly by enterprises as well as through managed service providers (MSPs) that manage IT systems for other organisations.

MSPs are an important channel because many smaller businesses rely on external IT providers rather than maintaining their own internal cybersecurity teams. Larger organisations also frequently work with external security specialists alongside their own teams.

Lennon says the platform helps MSPs maintain tighter control over the devices they manage.

“Before solutions like this, IT teams could deploy a new laptop and six months later it might have dozens of unauthorised applications running on it,” he commented. “With application control in place, the device stays in the same state months later as it did on day one.”

Dublin Hub and Hiring Plans

Although headquartered in Orlando, ThreatLocker maintains a growing operational presence in Ireland. The company operates a hub in Blanchardstown, Dublin, supporting customers across Europe and the UK.

Lennon, who leads operations for the EMEA region, is based in Dublin where the team continues to expand.

“When I joined in 2021 I was employee number sixty-seven,” he said. “Now the company has over seven hundred people worldwide.”

Sami Jenkins confirmed that the company is actively recruiting in Ireland.

“I’m travelling to Dublin next week to interview candidates,” she said. “We’re looking to hire more people in areas like sales and solutions engineering. Check out our website  for more information.”

A Fast-Growing Cybersecurity Company

Cybersecurity threats continue to evolve rapidly, particularly with the rise of ransomware and increasingly sophisticated phishing attacks.

ThreatLocker’s growth reflects increasing demand for preventative security approaches designed to stop malicious software before it can run. Its strict deny-by-default model represents a different approach from many traditional cybersecurity tools, focusing on preventing unauthorised activity rather than detecting attacks after they occur.

With continued international expansion and hiring in Dublin and Orlando, the company is positioning itself as a growing force in the global cybersecurity sector.

At Zero Trust World in Orlando, ThreatLocker also introduced new capabilities extending its platform further into network and cloud security. These developments, and their implications for strengthening organisational cybersecurity, will be explored in the next article.

Hear Danny Jenkins speak to Ronan Leonard last year on an Irish Tech News podcast.

Billy Linehan

Billy Linehan reported from Orlando, Florida where he attended ThreatLocker’s 6th Zero Trust World Conference at the Rosen Shingle Creek Hotel. Billy is a freelance writer covering innovation, tech for good and entrepreneurship, and is a regular contributor to Irish Tech News. He leads Celtar Advisers, working as a business mentor with SME and startup founders, and co-founded StartUp Ballymun, Dublin’s longest-running entrepreneurship series.

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