Mr. Marvin has been a member of the Oregon State Bar Since 1972. His prior experience was as a claims representative and a claims supervisor of CNA Insurance Companies and United Pacific Cascade Insurance Companies, which became Reliance Companies. While at CNA he developed expertise in the representation of architects and engineers when he was in charge of all professional liability claims in the State of Oregon. Later he was in charge of all professional liability claims involving $1 million or more on the West Coast. Since 1973, Mr. Marvin has provided professional and legal services to design professionals throughout Oregon.

Mr. Marvin was one of the organizers of the Construction Law Section of the Oregon State Bar and was one of the founders of the Oregon State Bar Professional Liability Fund. He is co-author of then "Owner-Architect/Engineer Agreements" Chapter  of the Oregon State Bar Construction Law and has made many presentations in construction and design law seminars for the design and legal professions. Mr. Marvin is a founding member of two subsections of the Oregon State Bar. The first subsection he helped form is the Construction Law Section and the second subsection is the Toxic Tort Section which is now known as the Product Liability Section.

He is a member of the American Bar Association, United States District Court Bar, Multnomah County Bar Association, and is admitted to pracice in all Oregon and Washington state and federal courts. Mr. Marvin has been expanding his practice into arbitration and mediation, and has presided over twenty cases in the last five years. His widespread practice occasionally takes him out of state in representation of various architects and engineers.