Opus Recruitment Solutions in Melbourne seeks a Senior Systems & Security Engineer to own end-to-end infrastructure and security projects, delivering modern Microsoft solutions for mid-market clients. The role is fully project-focused and involves CSPM and security stacks including Defender and Tenable. You will work with a team of engineers, collaborate with Solutions Architects, and apply Essential8, CIS, and NIST frameworks to ensure high-quality delivery and robust client outcomes.