Mr. Petri concentrates his practice in the area of commercial litigation. Throughout his career, he has represented multiple clients in a variety of areas, including residential and commercial construction, intellectual property, software and computer technology, ERISA, commercial contracts, products liability, physician / hospital disputes, employer / employee and insurance disputes.

Mr. Petri also has extensive experience in appellate practice. After graduating first in his class from the University of Missouri School of Law, he began his career as a clerk for the Honorable John R. Gibson of the United States Court of Appeals for the Eighth Circuit, and has practiced in the Eighth Circuit, the Missouri Court of Appeals and the Illinois Court of Appeals.