Security Lead - Member of Technical Staff

About the role

Callosum is seeking a Security Lead to own the design and assurance of security across their full-stack AI infrastructure. This role involves setting security architecture, translating complex customer requirements into technical engineering tasks, and leading security engagements for diverse deployment environments. You will build and manage a security team responsible for threat modelling, incident response, and operational security.

Responsibilities

• Define security architecture and requirements across our API, orchestration stack, agentic systems, and physical infrastructure
• Translate complex security requirements into specific engineering work, measurable guarantees, and verifiable evidence
• Lead security assurance for sensitive deployments from initial requirements through technical review and approval
• Build and lead the security team across architecture, threat modelling, adversarial evaluation, incident response, and operations

Required skills

• Security architecture
• Infrastructure engineering
• Threat modelling
• Incident response
• Security assurance

Qualifications

• Experience personally owning a demanding security assurance or sensitive deployment process end-to-end
• Strong technical foundations in infrastructure or security engineering
• Experience securing sovereign, on-premise, air-gapped, multi-tenant, or other high-assurance environments
• Experience building and leading security teams

Benefits

• Competitive Salary
• Equity
• Private healthcare
• Visa sponsorship
• Relocation benefits

About the Company

Callosum is an Intelligent Systems Company building the infrastructure that unifies heterogeneous compute across the full stack. They focus on software orchestration that co-evolves models, workflows, and silicon to deliver inference tailored to specific workloads.