Lieutenant junior grade Walter J. Pierce was a Starfleet engineer, a specialist in linear warp containment systems. Born on Epsilon Indi II, he was the son of Anita and Ambrose Pierce. He went to Starfleet Academy in San Francisco and had been the recipient of numerous decorations, including the Okuda Award in subspace research, the Jalhal Award for warp field engineering, and the Extended Tour Ribbon (with cluster). His service record included tours on the USS Chicago, the USS Suleiman, and the USS Umibazu before he began work at Utopia Planitia constructing the USS Enterprise-D. He served as assistant team leader installing engineering power conduits, and the warp engine local control systems.
Pierce was part Betazoid, and this left empathic traces in the nacelle tube bulkhead. These traces affected others and one crewmember, Daniel Kwan, killed himself in 2370. While investigating his death, Deanna Troi was also affected, but was saved at the last moment by Lieutenant Worf.