Lead Security Engineer

Harrison Clarke is partnering with a highly ambitious, well-funded AI company to hire its first dedicated security leader.

This is a true 0 to 1 security role. You’ll have the opportunity to define and build the security function from the ground up, while remaining deeply hands-on across security engineering, cloud infrastructure, application security, identity, corporate security, and emerging AI-specific threats.

What You’ll Own

• Build the security function from the ground up, including strategy, architecture, roadmap, tooling, and implementation
• Design and implement security across cloud infrastructure, identity and access management, endpoints, applications, and internal systems
• Establish security standards and controls without introducing unnecessary friction for engineering teams
• Develop threat models for complex AI and ML systems, infrastructure, and emerging attack surfaces
• Partner closely with engineering teams on architecture reviews, threat modeling, adversarial testing, and security improvements
• Take a hands-on approach to security engineering, including writing code and building internal tooling where appropriate
• Manage existing external security and IT partners while determining which capabilities should be brought in-house
• Establish the foundations required for future compliance initiatives such as SOC 2 and ISO 27001
• Own security incident preparedness, detection, response, and post-incident improvement
• Help shape the long-term security organization and eventually hire and develop a small, highly technical team

What We’re Looking For

• 8+ years of experience across security engineering, product security, infrastructure security, offensive security, or related disciplines
• A strong hands-on engineering background - this is not a purely managerial or governance-focused position
• Experience operating as the first or an early security hire, or significant experience building security capabilities in an early-stage environment
• Strong coding ability, ideally with Python, Go, or another systems/backend language
• Deep expertise in at least one security domain, combined with the breadth and curiosity to operate as a security generalist
• Strong understanding of cloud infrastructure, identity, application security, and modern software development environments
• An offensive security mindset, developed through areas such as red teaming, penetration testing, vulnerability research, security consulting, or adversarial testing
• Genuine interest in AI and the emerging security challenges associated with increasingly capable AI systems
• Comfortable operating with significant autonomy and solving problems where established playbooks may not yet exist
• Strong communication skills and the ability to work directly with engineers and company leadership