The Atacama Large Millimeter/submillimeter Array (ALMA) has operated successfully for more than a decade, remaining the world’s premier facility for high-resolution observations at millimeter/submillimeter wavelengths, with more than 5000 refereed publications to date. The next stage for ALMA is the Wideband Sensitivity Upgrade (WSU), which will increase the instantaneous bandwidth by 4× (initially delivered as 2×), improving its sensitivity and digital efficiency, while keeping the existing system in operation. This complex program requires dedicated systems engineering (SE) to maintain system integrity while scientific observations continue. We describe the complementary SE efforts at project and program levels, based on collaboration between the WSU Program Management Office, the Integrated Development Team, the JAO Systems Engineering Group, and regional development projects. We summarize the progress made towards System PDR and reflect on the SE and program management interplay.