Population-wide obesity prevention and treatment programs are fundamental to addressing the increasing overweight and obesity rates in socioeconomically disadvantaged populations. Innovative recruitment strategies, including proactive marketing strategies, are needed to ensure such programs have universal reach and target vulnerable populations. This study aimed to determine the success of proactive recruitment to Australia's Get Healthy Information and Coaching Service® (GHS) and to assess whether the recruitment strategy influenced participants' outcomes. Sociodemographic information was collected from all GHS participants who joined the service between February 2009 and August 2013, and anthropometric information regarding behavioural risk factors was collected from all GHS coaching participants at baseline and six months. Data were analysed according to the participants' referral source (self-referral and secondary referral versus proactive recruitment). Participants recruited through proactive marketing were more likely to be male, aged 50 years or older, have high school education, not be in paid employment and be from the lowest three quintiles of socioeconomic advantage. The risk factor profile of coaching participants recruited through proactive marketing did not vary significantly from those recruited via other mechanisms, although they were less likely to be obese and less likely to have a higher 'at risk' waist circumference measurement. Proactively recruited coaching participants reported significant improvements from baseline to six months (consistent with improvements made by participants recruited through other strategies), although they were significantly more likely to withdraw from coaching before they completed the six-month program.Proactive marketing facilitated use of an obesity prevention service; similar services may have greater reach if proactive marketing recruitment strategies are used. These strategies could be encouraged to assist such services to achieve optimal population impact among hard-to-reach populations.