Commander Marvin was born in Port Jefferson, Long Island, New York in 1965. His mother is a native of Mexico and his father is first generation Greek. He grew up in the San Francisco Bay Area and in 1987 moved to Texas and enrolled in the chemistry program at the University of Texas at Dallas. He graduated in May 1990 with a Bachelor of Science in Chemistry and subsequently received his commission from Officer Candidate School in Newport, Rhode Island in October of that same year.

Commander Marvin graduated Basic Underwater Demolition/SEAL training, class 176, in August 1991 and received his first assignment to SEAL Delivery Vehicle Team TWO in Norfolk, Virginia. There he received his military warfare designator as a Naval Special Warfare officer and later deployed to the Mediterranean with the fast attack submarine, USS L. MENDEL RIVERS (SSN 686) as the officer in charge of a combat mini submersible diving system.

His next military duty assignment was working plans and exercises in the Pacific theater of operations at the Naval Special Warfare command located on the island of Guam. After two years in Guam, he moved back to the Continental United States and did two tours of duty stationed in Norfolk, Virginia; one at SEAL Team FOUR as the Officer in Charge of a SEAL platoon where he deployed to South America and the other at SEAL Delivery Vehicle Team TWO as the Operations Officer.

In December of 2000, Commander Marvin was assigned to the Pacific Special Operations Command located in Hawaii and served as the Future Operations Branch Chief for two years. Upon completion of duty in Hawaii, Commander Marvin moved to the Middle East and was assigned orders as the Executive Officer at the Naval Special Warfare command located on the Island Kingdom of Bahrain. In November of 2004 Commander Marvin was transferred to the
Naval War College in Newport, Rhode Island where he received a Master of Arts in National Security and Strategic Studies the following year.

In December of 2005, Commander Marvin assumed the duties as Director of Operations at Naval Special Warfare Group FOUR in Norfolk, Virginia where he screened for command of a SEAL Team. Although selected for command, Commander Marvin declined his command orders and retired with 20 years of service in September of 2009 and moved to Seattle, Washington with his family. James now leads field operations and business development for an alternative energy start-up and has his own consulting practice.

Commander Marvin is married to the former Joanna Spicer Martel of Marblehead, Massachusetts. Mrs. Marvin received her Bachelor of Science in Business Administration from Trinity College in Vermont in 1989 and her Masters in Business Administrations from Troy State University in Norfolk, Virginia in 2000. James and Joanna have one daughter, Charlotte Marie Marvin who is six.