This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Information System Security Officer (Senior ISSO) based in the United States. This role provides cybersecurity leadership for critical information systems supporting federal mission environments. You will serve as a trusted security advisor, guiding organizations through Risk Management Framework (RMF) activities and continuous authorization processes. The position combines cybersecurity governance, technical coordination, documentation management, and risk management expertise. You will collaborate with system owners, engineering teams, security professionals, and government stakeholders to strengthen security posture. Your work will directly support compliance, vulnerability remediation, and operational readiness across complex environments. This is an opportunity to contribute to impactful cybersecurity programs while helping mature enterprise security practices.