Artificial Intelligence (AI) is gaining ground in school curricula worldwide, leading to an urgent need to train teachers in AI and data literacy. However, according to recent literature reviews, there is a lack of research-based professional development for teachers in these areas. In the following paper, we outline the steps we have taken to fill this gap by developing a 7-hour professional development program for teachers using the action research approach and evaluating it with 70 computer science teachers. The results show that the program has increased teachers’ perceived competence in introducing students to AI and improved their understanding of AI concepts. However, there is no clear evidence that a 7-hour program is sufficient for teachers to teach AI and data literacy related content in their classes.