Faculty development programs for internationalization of the curriculum in higher education are often evaluated for short- and medium-term outcomes, but more long-term assessments are needed to determine impact. This study examined the long-term (6 years) impacts on faculty from colleges of agriculture after participating in a one-year professional development program for internationalization, which included a two-week experience in Costa Rica with immersion in both pedagogical and global topics. The objectives of this study were to identify (1) the long-term impacts of the program and (2) the factors (program, personal, and environmental) that contribute to, or hinder, the success of internationalization efforts. Guided by social cognitive theory (Bandura, 1978), the researchers conducted semi-structured interviews with program participants (N = 8). Findings showed that perceived impacts varied considerably among participants and were highly dependent on their personal characteristics and their current environment, as predicted using social cognitive theory. Strengthened peer relationships was the most common and significant theme among participants, with sub-themes that included cross-departmental collaborations, a support group on campus, friendships/informal interactions, and validation of own scholarship. The other two themes included internationalization and new/broader perspectives.