Martin Madden was a Human male, a Starfleet commander who was originally assigned to succeed William T. Riker as first officer of the starship USS Enterprise-E in 2379 following Riker's promotion to Captain of the USS Titan. However, the position eventually went to Worf.
Madden transferred from the USS Talos to assume the duties of Enterprise first officer. Madden arrived on the bridge just as Riker was leaving. Madden, intent on making a good first impression with his new commanding officer, Jean-Luc Picard, requested advice from Riker regarding Picard's attitudes. Sensing the opportunity for a good joke, Riker misinformed his replacement, telling him that Picard was very laid back and preferred to be called "Jean-Luc." Madden took Riker's advice to heart, and only after receiving a withering stare from Picard as a response did he realize that Riker was "pulling his leg." (TNG novelization: Star Trek Nemesis)
Madden was played by actor Steven Culp in Nemesis, but his scenes were deleted from the theatrical release. Those scenes are reflected in the novelization, though, and were later included as extras on the Nemesis DVD.
The character was named after Marty Madden, long-time companion of Nemesis screenwriter John Logan.