T. Mertz was a Human Starfleet officer in the 22nd century.
In 2151, he was named as a Missions Operations officer on the dedication plaque of the Enterprise NX-01. (ENT: "Broken Bow", dedication plaque).
In January of 2155, he was named as a Booster Systems officer on directory placards at the Fleet Operations Center, Sol Sector. His office was in room #4319. (ENT: "Demons", directories)