Sr IT Security Engineer

Powering the world’s payments ecosystemACI powers the payments ecosystem – globally, and you power ACI. You’ll innovate, collaborate, and grow – in an energetic technology culture with decades of proven success. ACIers – in all roles and levels – are truly your colleagues and many are your friends. Our size and reach allow you to see the global impact of your work. You are visible, your talents are valued, and you are empowered to shape the future of payments.As a Sr. Security Engineer in Norcross, GA, you will join a diverse, passionate team, dedicated to powering the world’s payments ecosystem!Job PurposeThe Sr. Security Engineer is responsible for designing, implementing, hardening, and supporting enterprise security capabilities that protect company systems, platforms, and information assets. This role blends hands-on security engineering with operational execution across cloud security, security operations, incident support, and AI security use cases.The position partners with engineering, cloud platform, application, data/AI, and operations teams to reduce risk, improve detection and response outcomes, and support audit and control expectations. As a senior-level role, this position also contributes technical leadership through documentation, standardization, mentoring, and continuous improvement.Essential Functions and ResponsibilitiesDesign, implement, and continuously improve secure configurations and guardrails across enterprise and cloud environments, including identity and access controls, network protections, encryption, secrets management, logging, and platform hardening.Engineer, administer, and support enterprise security technologies spanning endpoint security, vulnerability management, SIEM/logging, identity management, monitoring, detection, and cryptographic controls.Drive remediation of security findings by prioritizing critical and high-risk issues, validating corrective actions, and improving repeatable control patterns.Build, operate, and enhance security operations capabilities, including detection engineering, SIEM/SOAR workflows, alert triage, investigation support, incident response playbooks, and operational runbooks.Conduct or support incident investigations, root-cause analysis, containment and eradication activities, and lessons-learned follow-through.Participate in the on-call support rotation for security incidents, provide technical support during active investigations and response activities, and contribute to post-incident remediation and continuous improvement.Develop and maintain technical documentation, engineering standards, implementation procedures, and evidence-quality artifacts to support operational consistency and audit readiness.Partner with engineering, cloud, application, and AI/ML stakeholders to implement scalable security controls and secure-by-default patterns.Perform technical assessments and proof-of-concept evaluations of new security solutions and recommend changes to procedures, standards, or tooling where appropriate.Implement practical security controls for AI-enabled systems and workflows, including governance, access controls, monitoring, and risk reduction for model and application use cases.Participate in audits, control reviews, and security assessments; support evidence collection, traceability, and remediation tracking.Mentor less experienced engineers and contribute to technical leadership across the team.Perform other duties as assigned and understand and adhere to all corporate policies, including the ACI Code of Business Conduct and Ethics.Qualifications (Education, Experience, Knowledge, Skills, and Abilities)Bachelor’s degree in Computer Science, Information Systems, Cybersecurity, MIS, or related field; equivalent practical experience may be considered.5+ years of experience in security engineering and/or security operations with demonstrated hands-on delivery.Strong working knowledge of security fundamentals across identity and access management, encryption, network security, secure logging/telemetry, configuration hardening, and vulnerability/risk remediation.Experience implementing and supporting security controls in at least one major cloud environment; direct experience across both AWS and Azure is strongly preferred.Demonstrated experience with security operations processes and tooling, such as SIEM/SOAR, detection engineering, alert triage, incident support, security scanning, or operational playbooks.Demonstrated ability to translate security findings into practical engineering improvements, documentation, and measurable operational outcomes.Experience developing technical documentation, standards, and runbooks for repeatable operational execution.Strong communication skills and the ability to work effectively with both technical and non-technical stakeholders.Ability to work independently on complex assignments with limited day-to-day supervision.Preferred QualificationsExperience with regulated or audited environments and supporting evidence traceability or control mapping.Experience with automation and scripting in Python, PowerShell, Bash, Go, Ansible, or similar tooling.Experience with policy-as-code, infrastructure-as-code security gates, or continuous compliance patterns.Experience with container, Kubernetes, or workload identity security.Experience with threat hunting, post-incident remediation, and engineering-driven control improvements.Familiarity with AI/LLM application security, threat modeling, secure evaluation/testing, and governance approaches.Advanced knowledge of security standards and frameworks.Experience mentoring junior team members.Licenses and CertificationsRelevant certifications are strongly preferred. Candidates should demonstrate credible competency across cloud security, cybersecurity operations, and AI / application security through a combination of certifications and directly relevant experience.Work EnvironmentStandard work environment.Majority of time spent on PC.Participation in an on-call rotation is required to support incident response, escalations, and urgent security events.Travel may be required on a limited basis.Applicants must be currently authorized to work in the United States on a full-time basis. This position does not offer sponsorship for employment visa status or work permit now or in the future.In return for your expertise, we offer opportunities for growth, career development, and a competitive compensation and benefits package—all within an innovative and collaborative work environment.Are you ready to help us transform the payments ecosystem? To learn more about ACI Worldwide, visit our web site at Job ID (Requisition #19838)ACI Worldwide is an AA/EEO employer in the United States, which includes providing equal opportunity for protected veterans and individuals with disabilities, and an EEO employer globally.Important Notice About Recruitment ScamsJob seekers should be aware of ongoing recruitment scams where individuals or organizations impersonate legitimate companies to offer fake job opportunities. These scams often involve requests for personal information, payments, or interviews through unofficial channels. Please be cautious and verify any communications claiming to be from our company ( / @aciworldwide.com). The ACI Worldwide recruitment team will always follow official channels and will never request payment.#LI-LF1#LI-HybridACI Worldwide is a global leader in mission-critical, real-time payments software. Our proven, secure and scalable software solutions enable leading corporations, fintechs and financial disruptors to process and manage digital payments, power omni-commerce payments, present and process bill payments, and manage fraud and risk. We combine our global footprint with a local presence to drive the real-time digital transformation of payments and commerce.Full timePosting Date: 2026-09-08