Objective North Korean refugee youths are at higher risk of developing a wide array of psychosocial sequelae, including increased impulsivity and problematic internet use. We aimed to identify reciprocal temporal relationships by performing autoregressive cross-lagged modeling and to examine how these relations differ by gender and adverse childhood experience. Methods We used the follow-up data of 108 North Korean refugee youths in South Korea over a 1-year period. The Barratt Impulsivity Scale-Brief and Young’s Internet Addiction Test were used to assess impulsivity and problematic internet use, respectively. Results Autoregressive effects were significant across all groups, indicating that impulsivity and problematic internet use were stable across time; however, prospective prediction of problematic internet use from impulsivity was not significant across all groups. Problematic internet use at baseline positively predicted impulsivity at after 1 year of follow up in only males and individuals with adverse childhood experience. Conclusion Our findings suggest that the negative effect of problematic internet use (i.e., increased impulsivity) among North Korean refugee youths may be more profound in males and those with adverse childhood experience. We present possible explanations for these findings and discuss the implications for targeted interventions.