Principal/Senior Applied Scientist Security Models Training Team - Next-Gen frontier research

The Security Models Training team is expanding to drive the development of a new type of GenAI architecture that can effectively address the unique challenges of cybersecurity. This is a unique opportunity to engage in frontier research that is product-focused at the same time. The Security Models Training team builds and operates the large‑scale AI training and adaptation engines that power Microsoft Security products, turning cutting‑edge research into reliable, production‑ready capabilities. As a Principal/Senior Applied Scientist, you will own end‑to‑end model development for security scenarios, including developing new model architectures, continual pre‑training, task‑focused fine‑tuning, reinforcement learning, and objective, benchmark‑driven evaluation. You will drive training efficiency and reliability on distributed GPU systems, deepen model reasoning and tool‑use capabilities, and embed Responsible AI, privacy, and compliance into every stage of the workflow. The role is hands‑on and impact‑focused, partnering closely with engineering and product to translate innovations into shipped, measurable outcomes, defining quality gates and readiness criteria, and mentoring scientists and engineers to scale results across globally distributed teams. You will combine strong coding, experimentation, and debugging skills with a systems mindset to accelerate iteration cycles, improve throughput and cost‑effectiveness, and help shape the next generation of secure, trustworthy AI for our customers.