Arns is the founder of The Arns Law Firm with offices in San Francisco and Reno, Nevada. He has specialized exclusively in representing families who have had catastrophic events occur in their lives, including serious injuries and death caused by defective products, construction site incidents, and other scenarios since 1975.
Arns is an adjunct professor of law at the University of San Francisco, teaching trial practice. He is on the Consumer Attorneys of California's (COAC) board of governors and the San Francisco Trial Lawyers Association's (SFTLA) board of directors, is a presenter in American Board of Trial Advocates Masters of Trial, is a frequent lecturer on consumer issues, and has been named to the Top 100 Super Lawyers in Northern California list.
Arns was named SFTLA Trial Lawyer of the Year 2004 (finalist 2000 and 2003) and was a finalist for COAC Trial Lawyer of the Year 2002, 2003, and 2004.
Arn's new office building has a built-in mock trial center. He has argued numerous cases in front of appellate courts, including the California Supreme Court and the U.S. Court of Appeals for the Ninth Circuit, and has resolved more than 250 seven- and eight-figure cases by verdict and settlements, including four eight-figure verdicts.