Mr. Klein practices in the areas of complex civil litigation, government relations, administrative hearings and appeals, appellate practice, and alternative dispute resolution. He has litigated cases involving construction contracts, insurance subrogation, patent infringement, destination clubs/time share, public access, Native Hawaiian rights, real estate exactions, closely held corporations, corporate governance and investigations, land use/ CC&Rs, constitutional rights, corporate taxation, serious bodily injury, and statutory construction and interpretation. Mr. Klein has appeared before state trial courts on Oahu, Maui, Kaua'i, and Hawai'i Island, the State Supreme Court, as well before the Federal District Court for the District of Hawai'i and the Ninth Circuit Court of Appeals.

He served as Associate Justice of the Hawai'i Supreme Court from 1992-2000 and in the trial courts of Hawai'i for 14 years from 1978-1992. He has authored hundreds of Supreme Court decisions during his tenure on the appellate bench.