Apple is seeking a Principal Machine Learning Engineer to join their ML innovation team, focusing on developing cutting-edge ML technologies that impact billions of customers. This technical leadership role involves working with both junior and senior engineers to design and implement ML solutions for personalization, memory, diagnostics, and reasoning. The position requires deep expertise in machine learning fundamentals, including mathematics, architectures, and generation processes. The role offers a competitive base salary range of $207,800 to $378,700, plus comprehensive benefits including stock options and bonuses. Located in Cupertino, this role presents an opportunity to work on transformative ML projects while leading cross-functional teams. The ideal candidate will have 7+ years of ML experience, strong technical skills, and the ability to translate complex requirements into innovative solutions. This position combines hands-on technical work with strategic leadership, making it perfect for those who want to shape the future of AI at one of technology's most influential companies.