Senior Systems Engineer - Identity & Authentication

• Senior Systems Engineer - Identity & Authentication 

• New York, NY (Hybrid, 3 days in office) 

• Highly competitive compensation package

Join an elite technology group at the forefront of global finance. We are seeking a Systems Engineer who operates at the intersection of deep infrastructure and software architecture. This is not an operational administration role; it is an architectural position responsible for the plumbing of the firm’s identity stack. You will bridge the gap between a mature Active Directory environment and a modern, cross-platform (Linux/Cloud), zero-trust ecosystem.

The Role 

While you’ll serve as the firm’s authority on the Microsoft Identity stack (AD/ADFS/ADCS), your mandate is interoperability. You will design authentication flows that allow seamless, secure movement between Windows, Linux, and Cloud environments. We need a builder who can look at legacy Kerberos implementations and architect their evolution into modern OIDC/OAuth standards without breaking the business.

What you’ll be doing

• Own the design and evolution of critical identity platforms (Active Directory, ADCS, ADFS), moving beyond maintenance to engineer resilience and scale.

• Bridge the OS divide and engineer the glue between Windows and Linux. You will solve complex challenges like cross-platform certificate enrollment (PKI for Linux/Unix) and heterogeneous authentication flows.

• Lead the technical migration from legacy auth to modern standards, implementing FIDO2/WebAuthn and transitioning apps from Kerberos to OIDC.

• Escape the GUI. Use PowerShell, C#, or Python to build custom tooling, automate lifecycle management, and treat infrastructure as code.

• Design robust mechanisms for managing the lifecycle of digital identities, secrets, and machine keys in a high-security environment.

You will bring:

Engineering over Administration: 10-15+ years of experience. You are an engineer who builds systems, not an admin who manages tickets.

Protocol Fluency: You have forensic knowledge of how authentication works (Kerberos logic, LDAP binds, OIDC flows), not just how to configure the tool that uses it.

The "Hybrid" Skill Set: Deep expertise in Active Directory and PKI is required, but you must be comfortable working alongside Linux Engineering teams to integrate non-Windows services.

Developer Mindset: Strong scripting/coding ability (PowerShell, C#, or Python) is essential for building automation and integration tools.

Complexity: Experience in large-scale, heterogeneous enterprise environments where "out of the box" Microsoft solutions often need custom engineering to work.