Originally known as Fredericks and Hanna, the firm was founded in 1915 by John D. Fredericks, formerly the District Attorney of Los Angeles County, and Byron C. Hanna, at one time Frederick's chief trial deputy. The firm was well known for its expertise in trial and appellate work. In recent years, while still known for its trial and appellate skills and its oil and gas expertise, the firm has developed expertise in environmental law, corporate transactions, real estate, energy regulation, foundations and trusts and general business law.