Ensign Dern was a Human Starfleet officer who served as an engineer aboard the starship USS Enterprise-D under the command of Captain Jean-Luc Picard.
Dern was on duty in main engineering when Geordi La Forge chose Lieutenant junior grade Reginald Barclay to accompany him on the away mission in 2369. He needed a systems engineer to beam on board the USS Yosemite. Barclay, suffering from transporter phobia, suggested Ensign Dern to beam aboard with the away team, but La Forge wanted Barclay. Dern remained in engineering to set up the remote link. (TNG: "Realm Of Fear")
Dern was played by unknown actor.