Although teaching artists have been conducting classroom residencies for decades, little attention has been paid to the type of professional development that prepares them for this work. When we see a good art lesson-whether in creative writing, dance, film, music, theater, or visual arts-we know that a lot goes into making it effective; this case study describes an innovative approach to the training of teaching artists and unpacks the processes that contribute to instructional effectiveness. A study of the core training elements of artist mentorship, teacher collaboration, and student assessment highlights their value in building the teaching artists' capacities to meet high educational expectations. Additionally, a deeper investigation into the behavioral dynamics between the artists and their classroom teacher partners reveals how instructional changes occurred. This book is of particular value for teaching artists and program administrators involved in their sponsorship and training. More generally, it provides an in-depth perspective for anyone interested in understanding the potential for broadening and deepening student learning experiences in and through the arts.