Cleared On Site Information Systems Security Officers (ISSO) (5359)

SMX is seeking a highly experienced Information System Security Officer (ISSO) – Sr to support a mission-critical federal program in Washington, DC. This individual will serve as a senior cybersecurity professional and trusted advisor responsible for ensuring the security, compliance, and operational integrity of enterprise information systems supporting critical mission functions. The selected candidate will function as the principal advisor to System Owners (SOs), Business Process Owners, Information System Security Managers (ISSMs), and cybersecurity leadership on all matters involving information system security. This role requires extensive experience implementing and maintaining security controls, supporting Risk Management Framework (RMF) activities, leading authorization efforts, and providing technical guidance across multiple systems and projects. The ISSO – Sr will serve as a technical expert responsible for evaluating security posture, mitigating risk, recommending security improvements, and ensuring compliance with federal cybersecurity requirements. This position is on site in Washington, DC and requires an active TS/SCI clearance.

Essential Duties Responsibilities:

Serve as the principal security advisor to System Owners (SOs), Business Process Owners, ISSMs, and program leadership on matters related to information system security

Lead implementation, maintenance, and continuous improvement of security controls across enterprise systems and applications

Direct and coordinate RMF activities including system categorization, control implementation, security assessments, authorization activities, and continuous monitoring

Develop, review, and maintain System Security Plans (SSPs), POA Ms, Security Assessment Plans, security procedures, and related authorization documentation

Evaluate system security posture and recommend corrective actions to address risks, vulnerabilities, and compliance deficiencies

Lead security reviews and assessments to validate implementation and effectiveness of security controls

Coordinate with engineers, system administrators, developers, and government stakeholders to ensure security requirements are integrated throughout the system lifecycle

Support Authorization to Operate (ATO) activities and ongoing authorization maintenance efforts

Direct vulnerability management activities including identification, remediation tracking, risk assessment, and validation of corrective actions

Review and validate access control implementations, privileged account management, hardware inventories, software inventories, and security configurations

Develop security reports, dashboards, metrics, and recommendations for government leadership

Support audit activities, compliance reviews, inspections, and security assessments conducted by internal and external organizations

Provide guidance regarding physical and logical protection of information system assets

Evaluate security program effectiveness and recommend improvements to policies, procedures, and operational practices

Support incident response, security investigations, and remediation activities as required

Lead major security initiatives and provide mentorship and guidance to junior cybersecurity personnel

Advise leadership on emerging threats, cybersecurity risks, and security modernization opportunities

Required Skills Experience

Active TS/SCI clearance required

Minimum of 8 years of professional experience supporting cybersecurity, information assurance, RMF, or information system security activities

Demonstrated experience serving as an ISSO, ISSM support resource, cybersecurity lead, or senior security practitioner within a federal environment

Extensive experience supporting Risk Management Framework (RMF) activities and Authorization to Operate (ATO) processes

Experience developing and maintaining SSPs, POA Ms, Security Assessment Plans, authorization artifacts, and related security documentation

Strong knowledge of NIST 800-53, NIST 800-37, FISMA, and federal cybersecurity requirements

Experience implementing, assessing, and maintaining security controls across enterprise information systems

Experience supporting continuous monitoring programs, vulnerability management, and compliance initiatives

Experience evaluating system security risks and developing risk-based mitigation strategies

Experience supporting audits, assessments, inspections, and compliance reviews

Strong understanding of access control management, security documentation, risk assessment, and security operations

Strong analytical, troubleshooting, and problem-solving skills

Ability to communicate technical security concepts to technical and non-technical audiences

Strong written and verbal communication skills

Ability to work independently while managing multiple priorities and supporting complex security initiatives

Desired Skills Experience

Bachelor’s degree in Cybersecurity, Information Technology, Computer Science, Info…