Senior ISSE & Data Engineer for Classified Cloud

Markon, Inc.; McLean (VA); On-site; USD 175,000 - 205,000; Full time

Job summary

Markon, Inc. seeks an experienced Systems Engineer with ISSE and data engineering expertise to support an Intelligence Community client in Chantilly.

You will design, secure, and optimize cloud and data solutions in classified environments, integrating security, analytics, and modern data practices. You will develop ETL pipelines, graph databases, and AI/ML-enabled workflows, while maintaining ATO artifacts, SSPs, and continuous monitoring.

Qualifications

• Active TS/SCI clearance with Full Scope Polygraph.
• Bachelor's degree and 8+ years of relevant experience; or Master's with 6+ years; or PhD with 3+ years; sponsor experience preferred.
• Demonstrated experience designing, securing, and maintaining data flow solutions in high-security environments.
• Strong ISSE experience including security architecture, A&A/ATO, vulnerability management, accreditation docs, and continuous monitoring.
• Hands-on experience developing ETL pipelines, data models, and data engineering for AI/ML initiatives.
• Proficiency in Cypher, Python, Java, or JavaScript; Neo4j experience preferred.
• Experience with graph databases, data cleaning, modeling, analysis, and visualization.
• Experience supporting sponsor mission systems or classified programs.
• Excellent written and verbal communication for technical and nontechnical stakeholders.

Responsibilities

• Lead ISSE activities across system lifecycle, including security architecture and compliance.
• Develop and maintain A&A documentation supporting ATO and SSPs/POA&Ms.
• Conduct security scans, vulnerability assessments, patching, and remediation in classified environments.
• Incorporate secure-by-design principles into architectures, data flows, and ETL pipelines.
• Design and optimize ETL pipelines for data integration and analytics.
• Develop Neo4j graph database solutions with data modeling and Cypher queries.
• Analyze medium-to-large datasets and create visualizations for mission decision-making.
• Build secure software components using Cypher, Python, Java, and JavaScript.
• Perform risk analysis, cost estimates, and trade studies; support CI/CD and Agile processes.
• Collaborate with engineers, security teams, and stakeholders to meet requirements.

Skills

TS/SCI clearance

Full Scope Polygraph

Security architecture

ISSE

A&A/ATO

Vulnerability management

ETL pipelines

Data modeling

Python

Cypher

Neo4j

Java

JavaScript

Graph databases

Cloud security

CI/CD

Agile

Data visualization

Education

Bachelor's degree

Master's degree

PhD

Tools

Neo4j

Cypher

Python

Java

JavaScript

Job description

Markon, Inc. seeks an experienced Systems Engineer with ISSE and data engineering expertise to support an Intelligence Community client in Chantilly.

You will design, secure, and optimize cloud and data solutions in classified environments, integrating security, analytics, and modern data practices. You will develop ETL pipelines, graph databases, and AI/ML-enabled workflows, while maintaining ATO artifacts, SSPs, and continuous monitoring.