This paper reports on the professional development of four mathematics teachers in South Africa. The four teachers all participated in a Mathematical Thinking (MT) course before taking an Advanced Certificate in Education (ACE) in mathematics. The research, which aimed to understand these teachers' ongoing professional development, took place two years after they had completed the ACE course, at a time when they were helping to run a subsequent MT course, taking the role of teaching assistants (TAs). The teachers provided written 'stories' of their experiences during and after the two courses and were interviewed twice after the two courses; the first interview drew on the stories and the second drew on the first interview. The qualitative data gathered were analysed using a three-part framework of outcomes: personal, professional and cultural/social. In terms of personal outcomes, they reported renewed confidence and passion for teaching mathematics, changed beliefs and values, and acknowledged new learning experiences; they did not, however, report on learning about mathematics, the curriculum or planning. In terms of professional outcomes, they reported changes in both their own classroom teaching practice and their approaches to leadership. Finally, there was little evidence of cultural/social outcomes, but participants reported on opportunities that had been offered to them and on new collaborations in their communities. We have called these 'community outcomes' and suggest that cultural/social outcomes might be renamed community outcomes so that it is extended to include these sorts of opportunities.