Active learning is becoming more widely accepted in mathematics as a superior teaching method for student learning and, as a result, faculty are increasingly convinced of the benefits. Our study was designed to close a research gap by determining how to support mathematics faculty in transforming their instruction to active learning. We investigated actual challenges of faculty during the transition to more active pedagogy, then researched and tested solutions to reported challenges. To do so, we executed a participant observation study of six diverse faculty members from a mathematics department and followed typological analysis techniques of focus group and interview transcripts. Participants' challenges include overcoming a dominant culture of teaching through lecture in the mathematics community, combatting a tendency to default to lecture, and acquiring specific skills and confidence to implement active learning. We suggest that specific characteristics of a robust department-wide professional development program could provide solutions to many challenges faced by faculty. This paper reports on the challenges for faculty, alongside proposed solutions through purposefully defined faculty professional development.