Professor Lahn directs Indiana Law's appellate advocacy program, teaching the principal Appellate Advocacy course and directing the Sherman Minton Moot Court Competition. He also teaches the Federal Courts Clinic, helps supervise students in the Private Practice Externship Program (B514) and the Public Interest Externship Program (B547), and directs the Inmate Legal Assistance Project. He has also taught legal research and writing, child advocacy, and mediation.
For the past decade, Professor Lahn has also volunteered his time as a faculty advisor to and volunteer attorney for the Protective Order Project, which has assisted victims of domestic violence living in Monroe and surrounding counties secure relief in the courts and access to community services since 1990.
Professor Lahn joined the Indiana Law faculty in 1995, bringing extensive legal experience in both government service and private practice. Lahn is a past recipient of the Law School's Leonard D. Fromm Public Interest Student Award (2001). This honor is awarded by students each year to the faculty member who has done most to encourage public interest work. He also received a University Teaching Excellence Recognition Award in 1998.
In 2005 and 2000, Professor Lahn took his teaching abroad to Indiana Law's partner schools, Assumption University in Bangkok, Thailand, and Adilet Law School in Almaty, Kazakhstan.
Professor Lahn has argued multiple cases in the Indiana Supreme Court, the Indiana Court of Appeals, and the United States Court of Appeals for the Seventh Circuit. In addition to his work with the Protective Order Project, Lahn has represented pro bono clients through District 10 and other area volunteer attorney programs. He is also an active member of the Indiana State Bar Association, having served as chair of both the Clients' Financial Assistance Fund (2004-06) and the Professional Legal Education, Admission and Development Section (2003-04) and as member of the Ethics Committee since 1998.