Scientists are increasingly being called upon to play a more prominent role in the interface of science and society by contributing to science literacy in ways that support two-way exchanges with the public. However, many remain reluctant to participate in public engagement activities in part because they feel they lack relevant skills and experience. We surveyed scientists trained on engagement through a nationwide program called Portal to the Public and examined how participation in the program may have influenced their self-efficacy, commitment and attitudes about outreach, and perceived benefits from conducting outreach based on two-way exchange with lay audiences. Participating scientists who responded to the survey reported being deeply involved in and highly committed to hands-on interactive public outreach, felt their engagement skills had improved, and even viewed benefits of their engagement training that extended into university teaching and career development. Our findings suggest a comprehensive engagement training model, which incorporates learning theory, helps scientists build their own outreach strategies, provides opportunities to practice, and offers easy access to audiences, can have a sustained impact on disposition, perceived skills, and type of outreach conducted by scientists interested in deeper engagement with the public.