The purpose of this study is to understand the mathematical content proficiency middle and high school teachers have before and after their first year teaching and taking graduate coursework in the Teach for America (TFA) program, as well as what attitudes toward mathematics TFA teachers have over the first year. There was a significant increase in both mathematical content proficiency and positive attitudes toward mathematics over the TFA teachers' first year teaching. TFA teachers generally believed the emphasis on social justice was of biggest benefit to them and that classroom management was the biggest problem faced in their teaching.