A junior systems engineer helps develop and maintain all computer systems for a business. As a junior systems engineer, your typical job duties involve installing, monitoring, and troubleshooting operating systems, software, hardware, and other computer infrastructure. A junior systems engineer helps develop and maintain all computer systems for a business. As a junior systems engineer, your typical job duties involve installing, monitoring, and troubleshooting operating systems, software, hardware, and other computer infrastructure. A junior systems engineer helps develop and maintain all computer systems for a business. As a junior systems engineer, your typical job duties involve installing, monitoring, and troubleshooting operating systems, software, hardware, and other computer infrastructure.