One of the Others that ambushed Sawyer and Juliet in the jungle following the flaming arrow attack on the remaining survivors wore a jumpsuit with the name Mattingly, which had belonged to a member of the United States Army. A young Charles Widmore, wearing a uniform labeled "Jones", appeared as the trio's leader, and Cunningham held Juliet while Mattingly was ordered by Widmore to cut off her hand. As he was about to do so, Locke attacked Mattingly with a rock. Mattingly recovered and was about to kill Juliet with the machete, when Locke hurled his knife into Mattingly's side. Mattingly collapsed and died. Locke then pulled the bloody knife out of Mattingly's dead body. ("The Lie") His body was later seen again during daytime. ("Jughead")
Given that Widmore was wearing a uniform with the name "Jones" on, it is likely that the uniforms were stolen, so it is likely that Mattingly is not his real name.
Ken Mattingly and Walter Cunningham were Apollo-era astronauts. Ken Mattingly was the command module pilot of Apollo 16.