Objective: The promotion of walking could be a feasible population-level physical activity strategy because it requires little planning, is low cost and can be done year-round across settings. Community, nonprofit organisations offer one means by which to help increase walking through community programmes. The US Cooperative State Research, Education, and Extension Service has a history that spans more than a century and is known for quality in the delivery of educational programmes to help improve the lives of people in communities across the USA. The purpose of this study was to evaluate the effectiveness, feasibility and acceptability of the Get WalkIN' intervention--an initiative supported by this programme--from the perspectives of both programme participants and county extension educators. Methods: Participants were recruited from 15 county extension sites in the Midwest region of the USA. Intervention emails targeted self-efficacy, social support, goal-setting and benefits/barriers to walking. To assess the perceptions of feasibility and acceptability of the intervention, participants and extension educators were asked to respond to a series of Likert-type scale and open-ended questions. Self-reported physical activity was assessed using the Godin Leisure-Time Physical Activity Questionnaire. Results: On average, participants and extension educators agreed that the programme was easy to use and would consider either recommending the programme to a friend or implementing the programme again within the community. Post-intervention, 69.1% of respondents were classified as sufficiently active compared to 60.5% pre-intervention. Conclusion: The use of the county-based US Cooperative State Research, Education, and Extension Service is an effective option for health promotion programming. Furthermore, a theory-based, email-mediated intervention is a valuable strategy as an independent and convenient way to facilitate increase in physical activity.