We sought to assess potential mechanisms of action of a patient navigation intervention in Head Start, designed to help depressed mothers engage with mental health care. We employed mixed methods, linking qualitative interviews (n = 21) to a randomized intervention pilot (n = 47). Early in follow-up, navigated mothers had lower mean depressive symptom scores than non-navigated mothers (9.61 vs. 12.95, p = 0.03). These differences attenuated but preceded a greater likelihood of engaging with care among navigated mothers. Navigated mothers reported greater self-esteem (score 21.45 vs. 18.60, p = 0.05) and greater confidence in their ability to self-manage depression (7.65 vs. 5.67, p = 0.01). In qualitative interviews, navigated mothers linked decreased symptom burden to feeling activated; they communicated optimism toward the future and a willingness to work toward symptom improvement by trying something new. Early symptom relief, behavioral activation, self-esteem, self-management, and optimism represent plausible navigation mechanisms of action. These constructs require formal testing. (author abstract)