Grant Yacomeni

Grant Yacomeni is the Chief Information Security Officer of Gigamon, appointed in September 2026. He reports to Chief Operating Officer Gareth Maclachlan.

Career path

Yacomeni is a United States Marine Corps veteran and served in intelligence and cybersecurity roles with the Maryland Army National Guard. He spent nearly ten years at the Department of Defense, where his last position was chief of the CISO staff. Across his time in the United States Intelligence Community, including the Department of Defense, he held leadership roles in which he led enterprise security programs and 24x7 defensive cyber operations. Gigamon named him Chief Information Security Officer on September 2, 2026, with the appointment made public the following day.

Remit at Gigamon

At Gigamon, Yacomeni leads information and product security, cybersecurity and IT operations, and governance, risk, and compliance. His focus is on managing cyber risk while enabling the business to operate securely, and he engages with customers and industry leaders as organizations evolve security strategies for hybrid cloud infrastructure shaped by artificial intelligence. The appointment followed Gigamon's 2026 Hybrid Cloud Security Survey of more than 1,000 security and IT leaders, in which 33 percent reported that their AI or large language model systems had been targeted in breaches over the past year.

Maclachlan said Yacomeni's background suited the moment facing security leaders working with AI-driven infrastructure. Yacomeni described the challenge AI poses for security teams directly: "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.

Published work and credentials

Yacomeni published a post on the Gigamon blog titled Hybrid AI Is Changing the CISO Mandate. He holds an M.S. in Computer and Information Systems Security from the University of Maryland Global Campus and is a Certified Information Security Manager.