This study aims to identify the factors determining the forestry household income in South Korea. An empirical analysis was conducted on the Korea Forest Service’s 3-year-panel data. Korea Forest Service is an institution responsible for the sustainable management of South Korea’s forest lands. In the study, the hypothesized factors determining the forestry household income are classified into four types of assets and three types of livelihood strategies. The forestry household income (FHI) is divided into three elements: forestry income (FI), non-forestry income (NFI), and transfer income (TI). The influence of household assets and livelihood strategies on each income were also assessed. A random effect model was used as a statistical analysis of the three-year data of 979 forestry households. Based on the analysis, we found that household head’s age, household head’s labor capacity, savings, business type, cultivated land size, and region are significantly associated with FHI. While FI was influenced by labor capacity, cultivated land size, business type, forestry business portfolio, and region, NFI was determined by household head’s age, household head’s gender, forestry business portfolio, and savings. TI was affected by household head’s age, household head’s education level, forestry business portfolio, savings, and region. The effect sizes and directions varied across different types of income (FHI, FI, NFI, and TI). The findings showed that South Korea forestry was highly dependent on sustainable assets and livelihood strategies. Based on our findings, we expect the effectiveness of forest policies in increasing the forestry household income would differ depending on the source of each income. The results of this study draw attention to the need for an income support policy which considers the characteristics of household assets and livelihood strategies in order to enhance FHI in South Korea.