Aleš Holeček

Developer, creator, and systems thinker - for more than three decades, I’ve worked on the architecture of large, complex platforms where security, reliability, and operational resilience are non-negotiable. My focus has been on designing systems that withstand real-world threats, evolve safely over time, and continue to perform under sustained global pressure.Today, as Chief Architect for Microsoft Security, I focus on strengthening the foundational architecture that enables platforms to be secure by design. That means reducing systemic risk, minimizing blast radius, and ensuring security decisions are embedded early, where they are most effective and least disruptive.Previously as CTO for Microsoft’s Experiences + Devices division, I helped guide the technical strategy and engineering execution behind M365 Copilot. Operating at that scale reinforced a simple reality: trust is earned through architecture. Security that works in practice comes from clear system boundaries, well-understood failure modes, and disciplined engineering long before controls, policies, or alerts are applied.What motivates me is building platforms customers can rely on to protect their data, support their people, and operate with confidence in an increasingly hostile environment.