Gigamon has appointed Grant Yacomeni as its chief information security officer (CISO), with the role reporting to chief operating officer Gareth Maclachlan.
The company said Yacomeni will lead information and product security, cybersecurity and IT operations, and governance, risk, and compliance (GRC).
Gigamon linked the appointment to the expansion of AI in hybrid cloud environments and the associated shift in security risk. Citing its 2026 Hybrid Cloud Security Survey of more than 1,000 security and IT leaders, the company said 33 percent reported their AI/LLM systems were targeted in breaches over the past year.
Yacomeni previously held leadership roles in the United States Intelligence Community, including the Department of Defense, where he led enterprise security programs and 24×7 defensive cyber operations, according to the company. Gigamon said he also served in intelligence and cybersecurity roles with the Maryland Army National Guard and is a U.S. Marine Corps veteran.
“Grant has spent his career operating in some of the world’s most demanding cybersecurity environments,” said Maclachlan. “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.”
Yacomeni said the spread of AI increases the operational speed and scale of security decisions for defenders.
“AI raises the stakes for security leaders because it can act on information at a speed and scale we haven’t faced before,” said Yacomeni. “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.”
