Dick D'Angelo was a member of Starfleet in the 24th century.
In 2353, D'Angelo was listed on a directory placard as having an office in room 75274 on Starbase 32. (TNG: "Violations")
He also was listed as a Starfleet Tactical official on the dedication plaque of the USS Pasteur. (TNG: "All Good Things...")
Furthermore, his name appeared in the USS Voyager crew manifest, retrieved from the computer in 2371. (VOY: "Projections")