Background: Research on the link between subjective health and unmet healthcare needs is limited. This study examines whether experiences of subjective healthcare needs and unmet needs are related to subjective health in South Korea, where the rate of poor subjective health is notably high. Methods: This analysis utilized data from the Korea Health Panel (2014-2018), incorporating 68,930 observations from 16,535 adults aged 19 or older. The dependent variable, subjective health, was dichotomized into poor (bad or very bad) and non-poor (fair, good, or very good) categories. The primary variables of interest were the experiences of subjective healthcare needs and unmet needs, while control variables included 14 socio-demographic, health, and functional characteristics. The study employed population proportion analysis and multivariable two-level binary logistic regression analysis for each gender, accounting for the complex sampling design. Results: In 2018, the rate of reporting poor health was 8.7% (95% confidence interval [CI], 8.0%-9.5%) for men and 14.7% (95% CI, 13.8%-15.6%) for women. For both genders, compared to individuals whose healthcare needs were met, those without healthcare needs were less likely to report poor subjective health (adjusted odds ratio [AOR], 0.58; 95% CI, 0.39-0.86 for men; AOR, 0.59; 95% CI, 0.37-0.93 for women). Conversely, individuals whose healthcare needs were not met were more likely to report poor subjective health (AOR, 2.31; 95% CI, 2.01-2.65 for men; AOR, 2.19; 95% CI, 1.98-2.43 for women). A policy simulation indicated that reducing the experience of subjective healthcare needs would be approximately 5 times more effective in reducing poor subjective health than a policy focused on reducing the experience of unmet needs. Conclusion: South Korea must make significant efforts to reduce the deterioration of subjective health and promote appropriate healthcare utilization. To achieve this, a set of policies is recommended to address subjective healthcare needs. These policies should include (1) prompting individuals to proactively manage their own health, (2) providing primary healthcare similar to that in advanced countries, (3) ensuring the healthcare delivery system operates effectively, (4) decentralizing the healthcare management system, and (5) reducing the likelihood of people being misled into thinking they have a healthcare need.