Mr. Cumberland graduated summa cum laude from California State University at Fresno (CSUF) in 1975, receiving a bachelor's degree in history. He attended law school at the University of Pepperdine and received his Juris Doctorate in 1980. Upon entering law school, Mr. Cumberland clerked at the firm of Stearns & Nelson in Los Angeles, which specialized in handling civil litigation claims by and against various public entities, business entities and the self-insured. After passing the bar in 1980, he was hired as an associate attorney at Stearns & Nelson and practiced with the firm until 1982. From 1982 to 1983, David worked for the firm of Goethals & Swanson in Orange County, a civil litigation firm. In 1983, after deciding to return to the Central Coast where he grew up, he accepted a position with the firm of Hoge, Fenton, Jones & Appel in San Luis Obispo, another civil litigation firm, where he worked until 1987.

In 1987, Mr. Cumberland was a founding principal in the San Luis Obispo law firm of Radovich & Cumberland, again, specializing in defense of commercial and insurance claims, as well as the defense of public entities. The firm became known as Radovich, Cumberland & Coates when Greg Coates joined the firm as a principal in 1989; it became Cumberland & Coates in 1995; and Cumberland, Coates & Duenow LLP, when Chris Duenow became a principal in 2002. In 2009, Mr. Cumberland joined Adamski Moroski Madden Cumberland & Green LLP as a partner in their Avila Beach office.

From 1987 to the present time, Mr. Cumberland has specialized in the defense of commercial and private clients, as well as the defense of public entities. During his career, Mr. Cumberland has tried over 100 cases to verdict including matters involving environmental contamination, professional negligence, breach of contract, premises liability, wrongful termination, gender and age discrimination, failure to supervise and/or train, sexual harassment, real estate and construction disputes, as well as personal injury claims alleging wrongful death, serious brain and other personal injuries.

Mr. Cumberland is currently a member of the San Luis Obispo County Bar Association and the Association of Defense Counsel for Northern California. He is also a member of the American Bar Association, the American Board of Trial Advocates (ABOTA), and is admitted to practice in all the courts of the State of California and both the California Northern and Central Districts of the Federal Court and the Ninth Circuit Federal Court of Appeals. Mr. Cumberland has also served as a court appointed arbitrator, discovery referee and judge pro tempore.

Mr. Cumberland is married, has two adult children, and resides in Arroyo Grande. In his spare time, he enjoys playing tennis, basketball, and other sports. Mr. Cumberland has also coached numerous athletic teams in the Santa Maria Valley and Arroyo Grande areas. He grew up in nearby Santa Maria and was selected as Santa Maria Valley Athlete of the Year in 1970, the year he graduated from Santa Maria High School. Mr. Cumberland attended UCLA and CSUF on baseball and basketball scholarships, and while attending UCLA, was a member of the "Walton Gang," which was led by Bill Walton, a future member of the National Basketball Association Hall of Fame. He also played minor league baseball with the San Francisco Giants after graduation from CSUF.