Objective: The goal of this study was to provide a greater understanding of physical activity in patients with early rheumatoid arthritis. The aim was twofold: first to explore if physical activity was associated with factors in the clinical picture of rheumatoid arthritis in this patient group, and second, to explore factors influencing physical activity in patients with early rheumatoid arthritis. Methods: A total of 66 patients with early rheumatoid arthritis were included in the study. A sequential explanatory mixed-methods design was used, where quantitative data from a questionnaire were analysed with Mann–Whitney, post hoc Kruskal–Wallis and χ² test in order to detect differences between groups, and find possible associations between physical activity and independent variables, such as disease activity, health-related quality of life and physical function. Qualitative data were collected in a follow-up questionnaire with open-ended questions that focused on factors influencing physical activity. Results: Associations between physical activity, disease activity and health-related quality of life were seen in patients with early rheumatoid arthritis together with strong negative correlations between physical activity and physical function. Patients on sick leave showed the strongest associations between disease-related variables and lower levels of physical activity. The findings from the qualitative analysis showed that physical limitations, awareness as a motivational factor and external environment factors influenced physical activity in patients with early rheumatoid arthritis. Conclusion: The results showed a complex underlying motive where physical, psychological and environmental factors influenced the physical activity in patients with early rheumatoid arthritis. In order to provide more effective health interventions, it is important to consider the complex nature of practicing physical activity, where a person-centred approach should be considered. Factors such as physical limitations, economic aspects and time for practicing physical activity should be included in the person-centred approach.