The Delivering Assisted Living Lifestyles at Scale (dallas) program was a large-scale, nationwide deployment of digital health and wellbeing products and services in the UK. Telehealth, telecare, mobile apps, personal health records, and assisted living technology were implemented by four large multi-stakeholder consortia and a multidimensional evaluation was carried out across the lifecycle from examining co-design and redesign of services through to rolling out services via statutory, private and consumer routes. A flexible toolkit of descriptive, process and outcome measures was developed and iteratively refined throughout the program. This approach enabled a longitudinal mixed-methods evaluation, underpinned by a robust social theory of implementation called ‘Normalization Process Theory’. There remains uncertainty about the best approaches to real world digital health evaluation. This program provided a unique opportunity to develop the knowledge base and toolkit of qualitative and quantitative methods necessary to evaluate person-centered digital health technologies deployed at scale.