This study, grounded in the job demands-resources (JD-R) model, explores how job crafting (approach and avoidance job crafting) affects burnout. It also investigates the moderating role of flexible working arrangements. Based on survey data from 456 full-time employees in China, the findings show that both approach job crafting and avoidance job crafting significantly reduce burnout. The interaction between approach and avoidance job crafting exhibits a synergistic effect, further reducing burnout. Additionally, flexible working arrangements strengthen the inverse relationship between approach job crafting and job burnout and mitigate the relationship between avoidance job crafting and burnout to some extent. However, flexible working arrangements have little impact on the combined effect of the two job-crafting strategies on burnout. This study enriches the theoretical understanding of the relationship between job crafting and burnout while providing practical insights for workplace management. It emphasizes the importance of flexible management practices and diverse work strategies in enhancing employee adaptability and reducing negative emotions.