H. Zimmerman was a mid 22nd century Starfleet officer.
In 2151, Zimmerman was noted on the dedication plaque of the Enterprise NX-01 for his work on the ship's spaceframe engineering. (Star Trek: Enterprise dedication plaque)
In January of 2155, Zimmerman was working in propulsion systems at the Fleet Operations Center on Earth. Zimmerman's office was in room 1201. (ENT: "Demons" set artwork)
H. Zimmerman, who was listed on pieces of background artwork, was named after production designer Herman Zimmerman.