Introduction: As COVID-19 restrictions reduce globally, services will determine what components of care will continue via telehealth. We aimed to determine the clinician, service, and system level factors that influence sustained use of telehealth and develop a framework to enhance sustained use where appropriate. Methods: This study was conducted across 16 allied health departments over four health service facilities (Brisbane, Australia). It used a multi-method observational study design, involving telehealth service activity data from hospital administrative databases and qualitative interviews with allied health staff (n = 80). Data were integrated and analysed using Greenhalgh's Non-adoption, Abandonment, Scale-up, Spread, and Sustainability framework. Results: Increased telehealth use during the peak COVID period reverted to in-person activity as restrictions eased. Telehealth is unlikely to be sustained without a clear strategy including determination of roles and responsibilities across the organisation. Clinician resistance due to forced adoption remains a key issue. The main motivator for clinicians to use telehealth was improved consumer-centred care. Benefits beyond this are needed to sustain telehealth and improvements are required to make the telehealth experience seamless for providers and recipients. Data were synthesised into a comprehensive framework that can be used as a blueprint for system-wide improvements and service enhancement or redesign. Discussion: Sustainability of telehealth activity beyond the peak COVID period is unlikely without implementation strategies to address consumer, clinician, service, and system factors. The framework can inform how these strategies can be enacted. Whilst developed for allied health disciplines, it is likely applicable to other disciplines.