Captain Herman Zimmerman was a Starfleet engineer and ship commander.
In 2363, Zimmerman was a member of the Engineering Group that was credited on the dedication plaque of the USS Enterprise-D. (Star Trek: The Next Generation set artwork)
A year later, in 2364, Zimmerman was in command of the USS Nightwing. In that year, prior to stardate 41775, his ship was assigned to the McKenzie Project. (TNG: "Conspiracy")
In 2370, Zimmerman was the captain of the USS Yorktown. His name was listed on the Deep Space 9 arrival roster. (DS9: "Whispers", production art)
In 2371, Zimmerman was listed as Science Ops personnel on the dedication plaque of the USS Defiant. (DS9: "The Search, Part I")
In 2372, Zimmerman was a member of the Engineering Detail credited on the USS Enterprise-E dedication plaque. (Star Trek: First Contact)
In 2375, Zimmerman was listed for Science Ops contributions on the dedication plaque of the USS Sao Paulo. (DS9: "The Dogs of War")