J. Longo was a 23rd century Starfleet lieutenant commander attached to the Starfleet Academy's Starfleet Training Command. Longo served as instructor for engineering.
In 2285, Longo was listed on a directory placard found on the 2nd level of Starfleet Training Command. (Star Trek II: The Wrath of Khan)
Longo was named after property master Joe Longo.