This article presents a mixed-method evaluation of the InsideOut Dad Program in three correctional facilities in New Jersey. The InsideOut Dad program aims to improve the parenting skills of incarcerated fathers through a 12-session curriculum. Using a quasi-experimental design, study participants (N = 309) and a control group (N = 104) completed pre- and post-test surveys, and a subset of program participants were interviewed before beginning and after completing the program. Class facilitators were also interviewed to assess perspectives on strengths and weaknesses of the program. Using 2 × 2, mixed-model ANOVA tests, results demonstrate that there were statistically significant changes in scales measuring fathering confidence, knowledge, attitude, and phone contact with children in comparison with the control group. The InsideOut Dad Attitude Scale showed no significant changes between the two groups. While qualitative responses were generally favorable, several areas for program development are identified. Implications for other fathering programs and implementation challenges are also discussed.