James Phillipsen started his career as a sound designer at The Dreamers Guild. Here he worked under Lawrence Schwedler as a sound effects designer on I Have No Mouth, and I Must Scream and Dinotopia in 1995. In 1997, he worked as co-composer on Halls of the Dead: Faery Tale Adventure II shortly before the company's bankruptcy. He subsequently had some roles scoring low-profile films including Dreamboy and the Clam.

In 2001, Phillipsen became the second member of the sound team of Richmond-based developer Nintendo Software Technology. He was asked to assist Lawrence Schwedler on Wave Race: Blue Storm and 1080° Avalanche as an additional composer and sound designer. He has also had additional audio roles on Ridge Racer DS, Metroid Prime: Hunters, and the Mario vs. Donkey Kong. He is expected to have a role on the long-delayed Project HAMMER next.