Though the research about teacher mentoring underscores the need of professional development for mentors. However, the case in reality is different and still we have little knowledge about what thoughtful novice science mentors do, and without any prior professional development, how they help their student teachers to become better teachers. The paper discusses a case study of an exemplary novice science mentor’s process of mentoring an intern from a Midwestern State University. Data includes five interviews, observations of teaching, mentor-intern interactions , and field notes. The articles describes how Julie Brad (pseudonym), performs her role as a mentor with a full load as a secondary science teacher and discusses how she learned to mentor in a particular way. The paper offers insight about significance of being critical and reflective of one’s own practice for self- professional development.