© 2016 Australian Health Promotion Association. Issue addressed Despite being viewed as a core competency for public health professionals, public health advocacy lacks a prominent place in the public health literature and receives minimal coverage in university curricula. The Public Health Advocacy Institute of Western Australia (PHAIWA) sought to fill this gap by establishing an online e-mentoring program for public health professionals to gain knowledge through skill-based activities and engaging in a mentoring relationship with an experienced public health advocate. This study is a qualitative evaluation of the online e-mentoring program. Methods Semi-structured interviews were conducted with program participants at the conclusion of the 12-month program to examine program benefits and determine the perceived contribution of individual program components to overall advocacy outcomes. Results Increased mentee knowledge, skills, level of confidence and experience, and expanded public health networks were reported. Outcomes were dependent on participants' level of commitment, time and location barriers, mentoring relationship quality, adaptability to the online format and the relevance of activities for application to participants' workplace context. Program facilitators had an important role through the provision of timely feedback and maintaining contact with participants. Conclusion An online program that combines public health advocacy content via skill-based activities with mentoring from an experienced public health advocate is a potential strategy to build advocacy capacity in the public health workforce. So what? Integrating advocacy as a core component of professional development programs will help counteract current issues surrounding hesitancy by public health professionals to proactively engage in advocacy, and ensure that high quality, innovative and effective advocacy leadership continues in the Australian public health workforce.