Join our Downer Professional Services team and play a key role in delivering complex defence and national security projects that safeguard Australia's future.Downer Professional Services comprises of three business units our Technical, Advisory, and Capability consulting practice, and Team Downer, which partners with CASG and NSSG as a major service provider to Defence. Together, we are a multi-disciplinary advisory and delivery partner of choice for clients across Defence and National Security.We currently have an opportunity for a Lead Technical Officer in Sydney to work on Modernisation projects.What You'll DoThis role offers a broad scope, with key role responsibilities including:Lead and manage the support team to resolve complex technical issues for mission‐critical Defence systems, including operations in DDIL environments and adherence to Defence ICT security protocols.Oversee integration and sustainment of complex ICT infrastructure, including messaging services in multi‐forest environments, application interoperability, hardware deployment, and digital certificate management.Maintain operational continuity through workarounds and contingency planning, ensuring system functionality in degraded conditions and providing escalation support for high‐priority incidents.Ensure governance and quality assurance by reviewing and approving SOPs, build guides, technical artefacts, and managing user accounts across Minerva environments.Develop team capability and stakeholder coordination, including mentoring staff, collaborating with partner teams and vendors, supporting ship CIS training, and managing incident priorities to meet SLAs.What You'll BringAdvanced administration expertise across Microsoft Exchange, Active Directory, Skype, Citrix VDI, and hypervisor platforms, with the ability to manage and maintain complex enterprise environments.Strong leadership and communication capability, demonstrated through prior management roles in support or service desk teams and the ability to collaborate effectively with diverse Defence stakeholders.Deep Defence ICT and ITIL experience, including work within Defence fleet environments, Level 3 incident management, high‐priority incident response, and implementation of monitoring and service‐level management practices.Broad technical breadth across Defence‐relevant technologies, including familiarity with Fortinet, Cisco, HYCU, Red Hat, Tanium, Carbon Black, Elastic, containerisation platforms, and previous Minerva system exposure.Proven ability to operate in secure, regulated environments, managing competing priorities, producing high‐quality written documentation, and restoring major Defence‐wide ICT issues with ITIL‐aligned certifications supporting practice.Due to the nature of the work, you are required to currently hold and maintain a minimum Negative Vetting 2 or higher Security clearance as required by the Commonwealth. In some instances, compliance with International Traffic in Arms Regulations (ITAR) requirements may also be an inherent requirement.More than anything, you'll bring a strong work ethic, a positive attitude, and a commitment to delivering high-quality outcomes for our clients.Why Downer Professional ServicesAt Downer Professional Services, we're not just a workplace - we're a business dedicated to contributing to the shaping of the future of defence in Australia. As the country's only sovereign prime, we're committed to making a real difference in protecting Australia's interests.What is means to belong at Downer Professional ServicesMeaningful work: Help to deliver critical Defence projects that protect Australia and shape its future.Professional development: Access career mapping, accelerated learning programs, and shared learning through our Communities of Practice.Great perks: Enjoy discounts on healthcare, retail, vehicles, and more through support: Benefit from initiatives like up to 20 days of Reservist Leave to stay connected post-service.You want your work to matter and so do we. With over 26,000 people across Australia, New Zealand and the Pacific, our team is made up of individuals with unique perspectives, backgrounds, and ideas.We know that diversity makes us stronger and we actively celebrate it through our commitment to inclusion and belonging.We're committed to building a team that reflects the diverse communities we serve and we welcome people of all ages, genders, sexual orientations, cultures, abilities, and lived experiences. We especially encourage applications from those whose voices have traditionally been underrepresented in our industry, including women, Aboriginal and Torres Strait Islander Peoples, Māori and Pasifika Peoples, veterans, people with disability, and neurodivergent individuals. Even if your experience doesn't align perfectly with this role, we'd still like to hear from you. If it feels like the right fit, apply - potential counts, and so do you.As a WORK180 Endorsed Employer, we support flexibility that works for your life, inclusive leadership that values your voice, and equitable access to opportunity so you can do your best work and bring your whole self to it.If you need support or adjustments through the recruitment process, just let us know, we're here to help you put your best foot forward.