This grounded theory qualitative study proposed developing a substantive theory describing the process of mental health orientation development in school counselors' professional identity across professional practice. Seven school counselors participated in semi-structured interviews exploring the experiences that shaped their mental health orientation. A conceptual model is presented that represents the process experienced by study participants. The conceptual model documents how the participants engaged in professional practice by encountering and responding to student mental health needs. These responses were influenced and/or supported by setting attributes and school counselor-initiated actions. Participants' mental health identity and alignment with the broader mental health profession were derived directly from their responsive services when encountering student mental health needs. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]