Multiple realities(covers information from several alternate timelines)
Brad Yacobian was a Starfleet officer in the 24th century.
As a vice admiral, he was listed as a Fleet Administration officer on the dedication plaque of the USS Brattain. (TNG: "Night Terrors", dedication plaque)
In 2353, he was listed as a Starfleet Operational Support Services officer on a directory placard at Starbase 32, Maxia Zeta. His office was located in room #35951. (TNG: "Violations", directory)
He was named as a member of the Fleet Ops team listed on the dedication plaques of the USS Voyager in 2371, and the USS Prometheus in 2373. (VOY: "Caretaker" dedication plaque; VOY: "Message in a Bottle", dedication plaque)
In an unknown, alternate future timeframe, as an admiral, he was listed as a Starfleet Command officer on the dedication plaque of the USS Pasteur. (TNG: "All Good Things..." dedication plaque)
This character was only mentioned in writing.