Gigamon names Grant Yacomeni as chief security officer

Gigamon has appointed Grant Yacomeni as Chief Information Security Officer, reporting to Chief Operating Officer Gareth Maclachlan.

Yacomeni will lead information and product security, cybersecurity and IT operations, and governance, risk, and compliance at the network security company. His appointment comes as businesses face a more complex threat environment tied to the wider use of artificial intelligence across hybrid cloud systems.

Before joining Gigamon, Yacomeni held leadership roles in the United States Intelligence Community, including at the Department of Defence, where he led enterprise security programmes and round-the-clock defensive cyber operations. He also served in intelligence and cybersecurity roles with the Maryland Army National Guard and is a US Marine Corps veteran.

The hire comes amid growing concern over how AI systems interact with applications, infrastructure, and sensitive data. Organisations are contending with a broader attack surface as AI becomes more deeply embedded in workflows and business processes.

Gigamon pointed to findings from its 2026 Hybrid Cloud Security Survey of more than 1,000 security and IT leaders. In the survey, 33 per cent said their AI or large language model systems had been targeted in breaches over the past year.

Security remit

In the role, Yacomeni will oversee internal security strategy while working with customers and industry figures on evolving security requirements in AI-linked hybrid cloud environments. His remit includes managing cyber risk while enabling the business to operate securely.

Maclachlan said the appointment reflects the changing demands on security teams as AI becomes more central to corporate systems.

"Grant has spent his career operating in some of the world's most demanding cybersecurity environments," said Gareth Maclachlan, Chief Operating Officer at Gigamon.

"His experience will be invaluable as we strengthen security across Gigamon and bring an even deeper practitioner perspective to our customers. As AI becomes increasingly embedded across hybrid cloud infrastructure, security, resilience, and business risk are becoming more interconnected. Grant is an outstanding addition to our leadership team at exactly the right time."

AI pressure

The appointment underlines how cybersecurity leadership roles are expanding as companies reassess the risks tied to AI adoption. Security leaders are under pressure to understand how AI models and agents use data, what actions they take, and whether the information behind those actions can be trusted.

For vendors such as Gigamon, the issue is also becoming customer-facing as buyers seek more visibility across cloud infrastructure, network traffic, and application behaviour. Yacomeni brings a practitioner perspective shaped by operational roles in national security environments.

Yacomeni said the speed and scale at which AI systems can operate is a key challenge for security teams.

"AI raises the stakes for security leaders because it can act on information at a speed and scale we haven't faced before," said Grant Yacomeni, Chief Information Security Officer at Gigamon.

"Security teams need trusted visibility into how data, applications, and AI systems interact so they can make better-informed decisions. I look forward to applying that principle inside Gigamon and working with customers as they evolve their security strategies for the Hybrid AI era."

Gigamon says it serves more than 4,000 organisations worldwide, including 83 of the Fortune 100, as well as mobile network operators and public sector agencies.