In the United States, firearm homicide is a major public health concern. Certain populations are at greater risk for being a victim of firearm homicide, such as those with prior criminal justice involvement. The overlap between violent victimization and offense history, referred to as the victim-offender overlap, is empirically supported, but research is limited on the overlap of firearm homicide victimization and justice involvement. Therefore, we examined the extent of victim-offender overlap of firearm homicide decedents by matching Illinois public health data with state arrest data. A total of 1,331 firearm homicide decedents were examined, including 20.4% (n = 271) with no arrest records and 79.7% (n = 1,060) with an arrest record, as well as 55.6% (n = 740) with a prior conviction and 31.8% (n = 423) with a prior incarceration. A higher proportion of firearm homicide victims with an arrest record were male, another race than White, non-Latinx, and single or never married than those without an arrest record. This study further supports the existence of the victim-offender overlap and highlights demographic disparities in criminal justice involvement among victims of fatal firearm violence.