His dissertation, Notice to Appear: Immigration Courts and the Legal Production of Immigrant Illegality, focused on the everyday practices and social control implications of immigration proceedings, as well as removal defense strategies within immigrant rights movements. His most recent project, the National Immigration Lawyer Survey (NILS), in collaboration with Dr. Maya Barak (University of Michigan-Dearborn) and Dr. Kathrine Abbott (University of New Hampshire), uses a mixed-methods approach to study the field of immigration lawyering and perceptions of procedural justice.

Before joining TRAC, Kocher taught at the University of Michigan-Dearborn and Western Governors University, and served in a leadership capacity at the Central Ohio Worker Center which he co-founded to provide advocacy to immigrants and low-wage workers in Columbus, Ohio. Kocher is currently chair of the Legal Geography Specialty Group within the American Association of Geographers and is active in the Law and Society Association.