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 Cunningham, which had belonged to a member of the U.S. 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. After Mattingly and Widmore were downed by rocks to the head, Sawyer tackled Cunningham and beat him with his fists. ("The Lie")
While Sawyer, Juliet, and Locke decided what to do with their prisoners, Cunningham attempted to converse with Widmore in secret via Latin, but Juliet understood them and revealed that all Others could speak Latin. She explained that the three soldiers were Others. When Juliet convinced Cunningham to tell them where his camp was, Widmore broke his neck. ("Jughead")
In the casting call Cunningham is described as "Mid-20s to Early 30s. Any ethnicity. Athletic, used to living outdoors and off the land. He is a loyal soldier but willing to compromise with the enemy to protect his men. A very nice recurring character."
Given that Widmore was wearing a uniform with the name "Jones" on it, it is likely that the uniforms were stolen, so Cunningham might not be his real name. However, Widmore referred to him as "Cunningham" when reporting to Richard Alpert, suggesting that Cunningham may have defected from the Army to the Others and was wearing his own uniform. ("Jughead")
Cunningham has a circular tattoo on his left wrist.