Background: A WW (formerly Weight Watchers) program adapted for persons with type 2 diabetes mellitus (T2DM) previously was found to be more effective than standard care (SC) intervention for weight loss, improved glycemic control, and weight- and diabetes-related quality of life measures. With data from the same national trial, this study examined whether WW adapted for persons with T2DM also increased engagement in weight control behaviors and decreased hedonic hunger, each of which could contribute to improved diabetes management. Intervention and methods: Individuals with T2DM (n = 563) and overweight or obesity participated in a 12-month, 16-site, randomized trial of WW with diabetes counseling or SC. Hierarchical linear modeling (HLM) evaluated whether 12-month changes in weight control behaviors (Eating Behavior Inventory; EBI) and hedonic hunger (Power of Food Scale; PFS) differed by treatment condition. If a significant treatment effect was found, 12-month changes in EBI/PFS were regressed on 12-month changes in HbA1c and percent weight loss to explore potential treatment differences in these associations. Results: EBI scores increased significantly over the 12-months (p < 0.001), with greater improvements in WW than SC (p < 0.001). PFS decreased significantly in the 12-months (p < 0.001), with no differences between treatment groups (p = 0.15). HLM analyses that followed up on the significant treatment effect for 12-month change in EBI revealed no significant differences by treatment condition for the relationship between change in EBI scores and change in HbA1c (p = 0.14) or percent weight loss (p = 0.32). Across all participants, 12-month improvements in EBI and PFS were related to improved HbA1c (r = 0.22; −0.13, respectively) and greater percent weight loss (r = 0.41; −0.18, respectively) (ps < 0.01). Conclusions: WW with diabetes counseling produced greater engagement in weight control behaviors in those with T2DM than did SC. Across both groups, improved weight control behaviors and hedonic hunger were related to improved glycemic control and weight loss.