Introduction: Incarceration represents an opportune moment to improve self-management of anger and aggression. A hatha yoga-based intervention (YBI) could serve as a useful adjunctive intervention for anger within prisons. Methods: We enrolled 40 people with elevated levels of anger who were incarcerated (20 in a women's facility, and 20 in a men's facility) in a 10-week pilot randomized controlled trial of a YBI versus. a health education (HE) control group. Participants attended their respective groups once per week. We examined indices of feasibility and acceptability, including intervention credibility, expectancy the intervention would be helpful, intervention satisfaction, class attendance, engagement in personal practice, instructor fidelity, intervention safety, and study recruitment and retention rates. We also examined changes in clinical outcomes including anger, depression, anxiety, and behavioral infractions over time. Results: We met targets for several outcomes: credibility of the YBI and HE interventions, expectancy that they would be helpful, and satisfaction with the programs. Instructors demonstrated fidelity to both manuals. There were no serious adverse events related to study participation. Class attendance did not meet our target outcome in either facility and rates of personal practice met our target outcome in the men's but not the women's facility. For people enrolled in the YBI, anger, depression, and anxiety tended to decrease over time. Qualitative interviews with participants pointed to overall high satisfaction with the YBI and provided information on facility-related barriers to class attendance. Conclusion: Although we did not meet all our feasibility targets in this study, we note high participant enthusiasm. Thus, we believe this line of research is worth pursuing, with further attention to ways to decrease facility-related barriers to class attendance and personal practice. Clinical trials registration: NCT05336123.