Director of Cyber Security (Deputy CSO) (m/f/d)

Rakuten Symphony Germany is building a nationwide mobile network based on the industry-leading Symphony platform developed from Singapore and successfully deployed in Japan. Symphony is a fully virtualized, cloud-native telco platform at the cutting edge of technology: Rakuten partners with research organizations, start-ups, and SMEs through its Network Innovation Lab on the future of OpenRAN and autonomous networks of the future. We are in the process of deploying a nation-wide mobile network in Germany.

Your Role

As the Deputy Chief Security Officer (Deputy CSO), you will serve as the operational backbone of Rakuten Symphony Germany’s cybersecurity organization. This is a high-impact leadership role that balances strategic oversight with hands-on technical command. You will act as the primary operational partner to the CSO, ensuring that our security posture is not only defined by policy but rigorously enforced and defended in our critical telecommunications and cloud-native infrastructure.

In this role, you will provide functional leadership to a 20+ person department, covering the full spectrum of cyber defense—from Red and Blue teaming to GRC, IAM, and Security Engineering. You will be the "boots on the ground" leader during critical security events, acting as the Incident Commander to guide our teams through high-stakes challenges.

We are looking for a leader who is as comfortable presenting security strategy to C-level stakeholders in Tokyo and Germany and bridge the gap between business objectives and technical execution, fostering a security-first culture while maintaining the agility required in a rapidly evolving telecom environment.

If you are a seasoned security executive who thrives in the trenches as much as in the boardroom, and you are ready to take full operational ownership of a global-scale security function, we want to meet you.

Your Responsibilities

• Disciplinary management of the Security Engineering, Operations, and Blue Team.
• Functional leadership of the entire Cyber Security department (20+ FTEs).
• End-to-End Incident Response Ownership: Full ownership of the Incident Response lifecycle - from maturing processes and playbooks to hands-on incident command during live crises, to managing external forensic/retainer agencies and stakeholder communication (authorities, clients, internal teams).
• Strategic Representation: Acting as the deputy for the CSO in communications with C-level stakeholders, both at the national (Germany) and corporate (Japan) levels. Reporting directly to the global CISO in Tokyo.
• Financial & Operational Oversight: Responsibility for the department’s budget, procurement processes, and contractor management.

Requirements

• Management Experience: At least 2 years of experience in disciplinary management within Cyber Security combined with significant seniority in Cyber security overall.
• Incident Response: Proven track record of successfully navigating at least one major cyber incident (e.g., ransomware) with the ability to lead response efforts across the organization.
• Execution: A strong, results-oriented mindset with a proven track record of driving security initiatives to completion.
• Technical Foundation: Engineering background with hands-on experience in at least one of the following: Offensive Security, Defensive Security, or Security Engineering. Solid understanding of Linux and Cloud-native environments (K8s).
• Cultural & Industry Context: Experience in the telecom industry is highly preferred. International experience (specifically working with cross-regional teams) is a significant plus.
• Fluent in English. German is a nice-to-have.