<p>Adverse childhood experiences (ACEs) are known to have lasting effects on well-being. This research studies ACEs, subjective happiness, and emotion regulation in young adults. Using a cross-sectional design, data was collected from a diverse sample of 323 young adults aged between 18 and 25 years (M = 21.08 years, SD = 1.94) from Gandhinagar, Gujarat and Jaipur, Rajasthan, India through self-report questionnaires assessing ACEs, emotion regulation strategies (cognitive reappraisal and expressive suppression), and subjective happiness. Results revealed a significant negative correlation between ACEs and subjective happiness (<i>r</i> = − .312, <i>p</i> &lt; .001) and between ACEs and cognitive reappraisal (<i>r</i> = − .243, <i>p</i> &lt; .001). However, no significant correlation was found between ACEs and expressive suppression (<i>p</i> = .586). ACEs, cognitive reappraisal, and expressive suppression emerged as significant predictors of subjective happiness (<i>p</i> &lt; .001, <i>p</i> &lt; .001, <i>p</i> = .001, respectively), collectively explaining 15.1% variance in subjective happiness. Additionally, cognitive reappraisal was positively correlated with subjective happiness (<i>p</i> &lt; .001), while expressive suppression was negatively correlated with subjective happiness (<i>p</i> &lt; .005). Males were found to engage in expressive suppression more than females (<i>p</i> &lt; .001), though there was no gender difference in the use of cognitive reappraisal (<i>p</i> = .054). It highlights the strong negative link between ACEs and subjective happiness, showing the long-lasting impact of childhood adversity on a person’s well-being. The study also highlights gender differences in expressive suppression, emphasizing the importance of considering gender-specific approaches in psychological interventions.</p>