Since closing the gap between different levels of professional development for teachers has been identified as a particular need in our profession, capturing the results of professional coursework can help teacher educators better understand and meet the unique needs of teachers with different levels of experience. This study examined the effects of professional development on early career (EC) and experienced (EXP) teachers during an advanced master's degree programme in the USA. Qualitative analysis of 47 teacher portfolio reflections and 11 post-programme interviews investigated how EC and EXP teachers engaged in programme learning experiences to determine the ways that coursework influenced their professional growth. Differences between EC and EXP teachers were noteworthy, indicating that these two groups responded to professional development experiences differently. Ongoing research to determine effective differentiated approaches toward professional development for both novice and EXP teachers remains a key area for teacher education research, most particularly with a goal of measuring the results of professional development on improving PK-12 student performance.