To aid departments in growing and supporting the potential of novice instructors, this paper shares a peer-mentoring program that has been implemented at three universities over the last five years for graduate student instructors (GSIs, master, and doctoral) within mathematics departments. This paper provides frameworks, curricular topics, necessary conditions, methods of implementation, successes, and anticipated challenges from five years of research to help establish and sustain a peer-mentoring program for GSIs. Positive outcomes from this peer-mentoring program included improving support for Novices (resulting in anticipating teaching concerns), lowering the rate at which students received a D, F, or withdrew (DFW), having fewer complaints and concerns, and sustaining stewardship.