<p>Little is known about the long-term effectiveness of responsible conduct of research (RCR) training and factors that support transfer of this learning to real-world settings after formal training concludes. We conducted a three-part study to explore short- and long-term effects of a culturally inclusive RCR training and a novel learning transfer intervention on professional decision-making skills. Biology and biomedical doctoral students across three cohorts participated in an RCR course focused on developing professional decision-making skills. In Study 1, students from Cohort 1 (<i>N</i> = 109) received the baseline control training, and students from Cohorts 2 and 3 (<i>N</i> = 195) received a revised culturally inclusive training. In Study 2, students from Cohorts 2 and 3 were randomly assigned to either a control group or a group receiving a monthly learning transfer intervention for 5 months after RCR training. The learning transfer intervention included identifying recent professional challenges, actions taken in response to challenges, and intentions to use professional decision-making strategies in the future. Study 3 involved follow-up interviews (<i>N</i> = 11) about experiences with the learning transfer intervention. Participants who received the revised training scored higher on professional decision-making compared to the baseline training. The learning transfer intervention did not improve self-reported use of professional decision-making skills. However, participants with low pre-course scores on professional decision-making saw sustained gains in these skills 6 months after the RCR training. Most participants interviewed about the learning transfer intervention perceived it as beneficial for being more reflective and intentional about using professional decision-making strategies.</p>