The recipient of a bachelor's degree in psychology from Oregon State University, Stephan O'Hair worked for the Oregon State University (OSU) Department of Public Safety as a student patrol lead officer while attending the school. Upon graduating, he began working as a reserve patrol officer with Philomath Police Department. Concurrently, Stephan O'Hair served as a skills trainer supervisor with Trillium Family Services, facilitating treatment plans for clients in collaboration with a clinical team and leading a variety of group therapy sessions such as dialectical behavior therapy and collaborative problem solving.

He later worked briefly as a mental health specialist with Oregon State Psychiatric Hospital and, since July 2017, has held the title of program operations director at ColumbiaCare Services. In this capacity, he provides short-term stabilization to patients undergoing mental health crises and works with community partners to ensure that those patients receive continued care upon leaving the Eugene-based facility.

In addition to his professional pursuits, Mr. O'Hair supports numerous nonprofits in the mental health sphere. Among them are the White Bird Clinic and Trillium Family Service's Keep Oregon Well Campaign.