G. Medina was a Human Starfleet officer in the 22nd century.
In 2151, he was listed as a Mission Ops officer on a dedication plaque of Enterprise NX-01. (ENT: "Broken Bow", dedication plaque)
In January of 2155, he was listed as a Telemetry officer on directory placards at Starfleet Command's Fleet Operations Center, Sol Sector. His office was located in room #3453. (ENT: "Demons", directories)
This character was only mentioned in writing.
He was named after construction foreman Greg Medina.