Roger began his legal career as a trial lawyer in San Jose, California, after graduating magna cum laude from the University of Santa Clara School of Law. As a partner in Matthews & Marzulla he represented developers, title and construction companies, shopping centers, apartment owners and lenders in litigation throughout California. In 1981 he moved to Denver to become President of Mountain States Legal Foundation, litigating environmental and natural resource cases across the West.
In 1983 Roger joined the Justice Department as Special Litigation Counsel. He was subsequently promoted to Deputy Assistant Attorney General and, in 1987, was confirmed by the Senate as Assistant Attorney General in charge of the Environment and Natural Resources Division. At the Justice Department, Roger helped create litigation strategies for government programs as diverse as Superfund, the Clean Air Act, off-shore oil leasing, environmental crimes, federal facility clean-up, wetlands, endangered species and hazardous waste enforcement, as well as Presidential Order EO 12,630 (Government Interference with Private Property Rights).
In 1989 Roger returned to private law practice, successively heading the environmental law practices of the Powell, Goldstein and Akin, Gump law firms.
Since 1997, as a partner in Marzulla Law, Roger has continued to represent corporate and business clients in a wide array of environmental and property issues in courts across the country, frequently in litigation against the United States. He also assists clients in attaining compliance with environmental, health and safety regulation, and in avoiding risks in transactions.