One collateral consequence of a criminal conviction for parents with young children is the loss of custody, which turns on the subjective “best interests of the child” standard. This research explored whether criminal conviction and substance abuse history influenced custody decisions. Experiment 1 presented community participants with a vignette describing a parent with combinations of manipulated stigmatized characteristics (i.e., gender, race, offender status, and substance abuse). Participants completed a custody determination scale, which showed that mothers with an offense received more favorable custody decisions than fathers with an offense, as did ex‐offenders without substance abuse. Experiment 2 added a positive or negative psychological fitness evaluation of the ex‐offender. It found main effects of the professional parenting evaluation and replicated the parent’s substance abuse findings from Experiment 1, but not the offense status result. Most importantly, these results were significant after controlling for the participants’ ratings of the best interests of the child in question and mediation analyses revealed that the child’s best interests only partially explained the relationships between substance abuse, the parental evaluation, and the custody determination. This suggests that participants made custody decisions based on factors extraneous to the current legal standard, namely, the best interests of the child.