Memory Alpha
Memory Alpha
Multiple realities
(covers information from several alternate timelines)

Gene Roddenberry was a Starfleet officer who served as the Chief of Staff of Starfleet Command during the late 24th century.

In 2353, he was listed as a Starfleet Operational Support Services officer on a directory placard for Starbase 32, Maxia sector. His office was located in room #15850. (TNG: "Violations", directory)

In 2357, William T. Riker was awarded the degree of Master of Science from Starfleet Academy. Roddenberry's signature was on the graduation diploma. (TNG: "Conundrum")

He was a flag officer with the rank of admiral in 2363. He was listed on the dedication plaques of several Federation starships. (TNG: "Encounter at Farpoint", "Silicon Avatar" dedication plaques; TNG: "The Wounded", dedication plaque; TNG: "Redemption II", dedication plaque; DS9: "Second Sight" dedication plaque; DS9: "The Die is Cast", dedication plaque; VOY: "Caretaker", dedication plaque; Star Trek: First Contact, dedication plaque; VOY: "Message in a Bottle", dedication plaque; DS9: "Valiant", dedication plaque; DS9: "The Dogs of War", dedication plaque)

On stardate 47302.5, Harry Kim was awarded the Cochrane Medal of Excellence from the Zefram Cochrane Institute for Advanced Theoretical Physics. Roddenberry's signature was on the award. (VOY: "Non Sequitur", set artwork [1])

In the anti-time future, 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.
He was named after Star Trek creator and showrunner Gene Roddenberry.
He was listed as a member of Starfleet Command at the Utopia Planitia Fleet Yards on the dedication plaque of the USS Odyssey. This plaque was made for the Star Trek: Deep Space Nine episode "The Jem'Hadar", but did not make an appearance in the episode. This plaque can be viewed at the twitter account of DS9's writer and producer Ira Steven Behr. [2]