The purpose of this mixed methods study was to explore the impact of a student teaching internship upon the classroom intercultural competence (CIC) of teacher education students and alumni. Phase I employed quantitative methodology to compare the intercultural competence as measured by Ross, Thornson, McDonald, and Arrastia’s (2009) Cross Cultural Competence Inventory (3CI) for three groups. The 3CI is a 63-item survey that uses corresponding questions to assess intercultural competence. Survey items are scored with a 6-point, strongly agree-to-strongly disagree Likert scale (Thornson, 2010). The three groups included teacher education students enrolled in a field observation course, students enrolled in their student teaching internship, and teacher education alumni currently teaching in the Jacksonville metropolitan area. Participants’ 3CI scores were used as a diagnostic tool to facilitate the recognition of factors relative to their overall intercultural competence. Three quantitative research questions were tested: Is there a statistically significant difference between matched pairs of intern’s CIC as measured by the scales and subscales of the 3CI (Ross et al., 2009) after students complete their field observation experience as compared to their pre-field observation scores? This question was not supported (t(116) = 1.07; p > .05). Do matched pairs of interns who experienced an IST enhanced internship (Ross et al., 2009) as compared to matched pairs of interns whose student teaching experience was exclusively in a domestic classroom? This question was supported (t(38) = 1.68; p < .001; d = .252). Do in-service teachers who experienced an IST enhanced internship demonstrate increased CIC as measured by the scales and subscales of the 3CI (Ross et al., 2009) as compared to in-service teachers whose student teaching experience was exclusively in a domestic classroom? This question was not supported (t(25) = .93; p > .05). Each of the 6 subfactors was charted to portray a graphic illustration of the areas of strengths and weakness concerning classroom intercultural competence. In the qualitative component of the present study, interview methodology facilitated gathering qualitative data from intern and in-service teachers. This provided a context for enhancing the quantitative data and for addressing the unique nature of how different individuals learn to adapt to diverse students in the classroom. One qualitative research question was tested: To what extent do qualitative data collected from interviews reflect similar areas of growth as indicated by the scales and subscales of the 3CI (Ross et al., 2009) quantitative measurement? Interviews with these teachers led to the identification of significant factors related to intercultural communicative success in the multicultural classroom. Hence, research question 4 was supported.