New York City Metropolitan Area, United States, January 2026 — John Callery has joined Citadel as Head of People Operations, where he will lead the firm’s people operations agenda, strengthening workforce strategy, analytics, systems, and global HR operations to support Citadel’s high-performance culture and global growth.
John Callery joins Citadel after a highly impactful tenure at Gartner, where he most recently served as Senior Vice President, HR Strategy & Operations. In this role, he established and led Gartner’s global HR Strategy & Operations function, driving enterprise-wide transformation across analytics, systems, planning, and operations. His work significantly improved workforce economics, enhanced productivity and agility through real-time analytics, and supported Gartner’s rapid workforce expansion through the Great Resignation. He also co-led the organization’s post-COVID hybrid and location strategy and led global office reopening efforts.
Prior to this, John held leadership roles at Gartner including Group Vice President and Managing Vice President, People Analytics, where he led global analytics, workforce planning, talent acquisition, and HR technology teams supporting a workforce of over 20,000 employees.
Earlier, he spent nearly four years at BNY Mellon as Managing Director, Global Head of Workforce Strategy, where he built enterprise workforce analytics and planning capabilities for a 50,000+ employee organization and advised the Executive Committee and Board on strategic people and pay equity initiatives.
John also brings entrepreneurial experience as Co-Founder & CEO of Rolic, along with senior people analytics leadership roles at AOL and PTC, and early technical experience with NASA Langley Research Center.
Citadel is a leading global investment firm with an ambition to be the most successful investment firm of all time. For more than three decades, Citadel has captured undiscovered market opportunities by empowering extraordinary people to pursue bold ideas and by identifying the highest and best uses of capital to deliver superior long-term returns for the world’s preeminent public and private institutions.
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