Provides executive administrative support to three C-level executives, including complex calendar management, travel coordination, meeting logistics, and confidential information handling. Manages the South San Francisco office, supplies, vendors, mail, equipment, and facilities requests. Coordinates R&D interviews, onboarding activities, safety trainings, advisory meetings, and company culture events. The role is fully on-site with occasional travel and requires strong organization, discretion, communication, and multitasking skills.