Our client, a pioneering technology firm, is looking for a Senior Mechanical Systems Engineer to join their world-class engineering team based in the heart of innovation in **San Francisco, California, US**. This role is integral to the design, development, and integration of complex mechanical systems for our groundbreaking products. You will be responsible for leading projects from concept through production, ensuring the highest levels of performance, reliability, and efficiency. Key responsibilities include defining system requirements, creating detailed mechanical designs using CAD software (e.g., SolidWorks, Creo), performing advanced simulations and analyses (FEA, CFD), and collaborating closely with cross-functional teams, including electrical engineering, software development, and manufacturing. You will also oversee prototyping, testing, and validation processes, troubleshoot design issues, and contribute to continuous improvement initiatives. The ideal candidate will hold a Master's degree in Mechanical Engineering or a related field, with a minimum of 7 years of relevant professional experience in mechanical design and systems engineering, preferably within the technology or advanced manufacturing sectors. Proven expertise in thermal management, fluid dynamics, materials science, and electromechanical systems is highly desirable. Strong proficiency in CAD/CAE tools and a deep understanding of manufacturing processes are essential. Excellent analytical, problem-solving, and communication skills are required, along with the ability to lead technical discussions and mentor junior engineers. This on-site position offers the opportunity to work on cutting-edge projects in a collaborative and intellectually stimulating environment, driving innovation and shaping the future of technology.