Objective This paper describes the 4-year journey of Hunter and New England HealthPathways - a password-protected web-based portal designed to provide localised evidence-informed clinical and referral information to support general practice at the point of care. Methods A process evaluation was conducted in 2013, with a case study comparison performed in 2014 to assess impact of HealthPathways on patient referral and access to specialist care, followed by a review in 2016 of utilisation of the online portal to assess whether healthcare providers continued to access HealthPathways. Results Increased utilisation was correlated with an increase in the number of pathways published online. Clinical leadership and the process of developing pathways built relationships between primary care and specialist teams. Case studies indicated that a comprehensive approach to pathway implementation accompanied by service redesign resulted in higher pathway use and improved access to specialist care. Senior management support and a formal partnership between major health care providers led to strong governance of HealthPathways and the delivery of other integrated care initiatives. There was significant growth in utilisation over the 4 years, increasing to an average of 6679 sessions per month in 2016 and more general practices reported use of HealthPathways. Conclusions HealthPathways is a vehicle for building strong foundations to support system change and integrated care. The critical elements for acceptability, growth and sustainability are the strong relationships between primary care and specialist clinicians, as well as formal partnerships that are built from the processes used to develop HealthPathways. What is known about the topic? HealthPathways and similar web-based evidence-informed guidelines aimed at improving system integration are increasing in Australia. There are few published papers that describe approaches to inform the ongoing implementation of such programs. What does this paper add? This paper describes iterative methodology for evaluating complex programs, such as HealthPathways, that identifies the critical factors required to build sustainable models of integrated care. What are the implications for practitioners? The 4-year experience of Hunter and New England HealthPathways provides an approach to improve the implementation, sustainability and spread of similar programs and associated integrated care initiatives.