I Forgot Star Trek: The Next Generation Had Another First Officer Besides Riker

The USS Enterprise-D briefly had another First Officer besides Commander William Riker (Jonathan Frakes) on Star Trek: The Next Generation. Throughout TNG's seven seasons, Commander Will Riker turned down numerous promotions to remain on the Enterprise. Riker gained a reputation as one of the finest First Officers in Starfleet. Sometimes situations dictated that another person had to step into the position of First Officer, but one Riker replacement was particularly unique.

In Star Trek: The Next Generation season 5, episode 14, "Conundrum," the entire crew of the USS Enterprise-D suddenly suffers amnesia. No one can remember their names or duties, although they still know how to operate a starship. Riker suggests that Captain Jean-Luc Picard (Patrick Stewart) is the leader because of the four pips on his collar, while Lt. Worf (Michael Dorn) suggests he could be the leader because of the Klingon baldric he wears. What they don't realize is that a new crew member has mysteriously appeared, later revealed to be the Enterprise's First Officer, Commander Kieran MacDuff (Erich Anderson).

Star Trek: The Next Generation’s Other First Officer Explained

Who Was Commander Kieran MacDuff?

After losing their memories, the USS Enterprise-D's crew eventually discovers a list of senior officers in the ship's computer. This roster lists Commander Kieran MacDuff as the ship's First Officer, and Commander Riker has been bumped to the Enterprise's second officer. While viewers know Commander MacDuff is not what he seems, the ship's crew has no reason to suspect that anything is amiss with their First Officer. By tampering with the ship's computer, MacDuff and his people convince the Enterprise crew that they are at war with a species called the Lysians.

Commander MacDuff encourages the crew to follow their supposed mission objective and destroy the Lysian command center. Counselor Deanna Troi (Marina Sirtis) senses that something is off, and Captain Picard begins having doubts about the nature of their mission. Eventually, Commander MacDuff is revealed to be a Satarran posing as an Enterprise officer in an attempt to use the ship's firepower to defeat the Lysian Alliance. When MacDuff tries to fire the Enterprise's weapons himself, Commander Riker shoots him with a phaser, revealing his true identity.

Other First Officers Replaced Commander Riker In Star Trek: The Next Generation

Riker Was Only Replaced A Handful Of Times On TNG

Although "Conundrum" was the only time a mysterious character took over as First Officer with no explanation, there were other instances on Star Trek: The Next Generation where another Starfleet officer filled the position. In the epic TNG two-part episode, "The Best of Both Worlds," Captain Picard is kidnapped and assimilated by the Borg. This leaves Riker in command of the USS Enterprise-D, and he's granted a temporary field promotion to Captain. Riker chooses Lt. Commander Elizabeth Shelby (Elizabeth Dennehy) as his First Officer, despite their professional rivalry.