Principal Machine Learning Engineer, AI & Data Platforms (AiDP)

At Apple, we build AI systems that define experiences for billions of people and we do it with an unwavering commitment to privacy, performance, and craft. The AI & Data Platforms (AiDP) team is seeking a Principal Machine Learning Engineer to lead the design, fine-tuning, evaluation, and productionisation of large language models and generative internal AI systems at global scale. This is a deeply hands-on, high-impact role: you will work across the full model lifecycle, from reinforcement learning and upstream training through to deployment of standalone, customer-facing products. The ideal candidate is equal parts researcher, engineer, and product builder. You bring authoritative depth in LLM customisation and alignment, a sharp instinct for performance and quality, and the ability to ship end-to-end AI-powered products that meet Apple's standard of excellence. If you thrive at the intersection of frontier model development, systems engineering, and product creation we want to hear from you.