This study aimed to investigate factors associated with breastfeeding for at least one year among women in Chiang Mai, Thailand. We conducted a cross-sectional study of 451 mothers with children aged between 12 and 24 months who visited the well-baby clinic among women who visited the well-baby clinic in secondary and tertiary hospitals. The data collected included maternal sociodemographic information, employment status, reasons contributing to continued breastfeeding, primary sources of information, and influential people affecting continued breastfeeding. Multivariable logistic regression analysis was used to investigate the relationship between explanatory variables and continued breastfeeding at one year. Reporting “easier to bond with baby” as a reason to continue breastfeeding (AOR 3.118, 95% CI: 2.022, 4.809) and multiparous status (AOR 1.588, 95% CI: 1.042, 2.420) were positive predictors of mothers who had breastfeeding at least one year postpartum while mothers with undergraduate education level (AOR 0.635, 95% CI: 0.404, 0.997) were more likely to discontinue breastfeeding. Our study highlighted that working mothers have lower odds of continued breastfeeding than stay-at-home mothers (SAHMs), which was found for work with day shifts (AOR 0.437, 95% CI: 0.261, 0.731), work with rotational shifts (AOR 0.481, 95% CI: 0.247, 0.934), and work from home jobs with a flexible schedule (AOR 0.439, 95% CI: 0.229, 0.838). These findings showed that both employment outside home and work from home were strong risk factors for discontinuing breastfeeding before 12 months. We suggest that a breastfeeding-friendly workplace policy is essential to enhance the continuance of breastfeeding. Additionally, working at home requires more research to explore breastfeeding barriers and establish more support strategies.