Dan Gelston

Chief Executive Officer Constellis Holdings

Last Reviewed: September 18, 2026

Executive Summary

Dan Gelston became Chief Executive Officer of Constellis Holdings in February 2026, taking over a company of more than 11,000 people that provides integrated security, training and risk management services to governments and commercial clients worldwide. His career reads as a single continuous line through the national security economy rather than a series of pivots: an Army armor and military intelligence officer through the post-9/11 years, then a counterterrorism targeting analyst producing intelligence for senior government officials, then twenty years running defence and security businesses — communications systems at L3Harris, detection and tactical communications at Smiths and Cobham, training and simulation at CAE, and most recently enterprise AI for federal agencies at C3 AI. What he has repeatedly been hired to do is take a defence business through a structural change — a turnaround, a carve-out, an acquisition, or the standing-up of an entirely new unit — and make it grow.

Career Highlights

• Appointed Chief Executive Officer of Constellis Holdings on 10 February 2026 in a planned transition, succeeding Terry Ryan, who had led the company for five years.
• Founded and led C3 Federal Systems, the federal government business unit he launched after joining C3 AI in February 2024.
• Group President of CAE Defence & Security and Chief Executive Officer of CAE USA Inc. from August 2020, running a roughly $2 billion global business with more than 6,000 employees.
• President of L3Harris Technologies’ Broadband Communications Systems sector and its Communication Systems-West division, where the business delivered record fiscal performance.
• Led the Special Security Agreement businesses at Smiths Detection Inc. and Cobham Tactical Communications, including a $710 million acquisition and several divestments.
• Led Cobham Surveillance through its 2015 sale and transition to standalone operations.
• Served in the U.S. Army on active and reserve duty from 1998 to 2007 as an armor and military intelligence officer; U.S. Army Armor School Draper Awardee and Distinguished Honor Graduate of the Intelligence Officer School.

Professional Journey

Gelston studied economics and international strategic policy at Bucknell, then served in the U.S. Army from 1998, on active and later reserve duty, as an armor officer and then a military intelligence officer. He was recognised with the Draper Award at the U.S. Army Armor School and graduated as Distinguished Honor Graduate from the Intelligence Officer School, and he took a master’s in strategic intelligence at the National Intelligence University. His first civilian posting stayed inside the same world: counterterrorism targeting analyst in the intelligence community, producing intelligence products for senior government officials.

He moved into industry through the security technology sector, where his pattern of work established itself. At Cobham he led the Surveillance business through its 2015 sale and transition to standalone operation, and he ran the Special Security Agreement businesses — the ring-fenced entities that allow foreign-owned firms to hold US classified contracts — at both Cobham Tactical Communications and Smiths Detection Inc., handling a $710 million acquisition and a series of divestments along the way. At L3Harris Technologies he was President of the Broadband Communications Systems sector and of the Communication Systems-West division, which posted record financial results under his leadership.

In August 2020 CAE recruited him as Group President of its Defence & Security group and Chief Executive Officer of CAE USA Inc., succeeding an interim leader. That was the largest operating job of his career to that point: roughly $2 billion in revenue, more than 6,000 employees, and a business built on military training and simulation across multiple national customers. He held it for close to four years.

In February 2024 he moved to C3 AI to build something from nothing, founding and running C3 Federal Systems — the unit created to sell the company’s enterprise AI platform into US government agencies, a market with procurement and accreditation constraints that general enterprise software vendors routinely underestimate. Two years later, in February 2026, Constellis named him chief executive in a planned transition from Terry Ryan. The role brings him back to physical security and training delivery at scale, now with the AI deployment experience layered on top.

Education

National Intelligence University

Master of Science, Strategic Intelligence

Bucknell University

Bachelor’s degree, Economics and International Strategic Policy (double major)