Own the post-sale customer lifecycle for B2B SaaS accounts, including onboarding, rollout coordination, issue resolution, account health, renewals, retention, adoption, and expansion. Lead cross-functional communication with customers and internal teams, document feedback and action items, identify churn risks and upsell opportunities, and standardize customer success processes. Requires high autonomy, urgency, strong communication, and comfort with CRM systems, workflow automation, and multi-site deployments.